🕷️ Crawler Inspector

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Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 152 (from laksa106)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa152.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://en.wikipedia.org/wiki/Arrhythmia\')), getAhrefsUnparsedNoserviceFromURL(\'https://en.wikipedia.org/wiki/Arrhythmia\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/en.wikipedia.org\/wiki\/Arrhythmia","crawl_time":1775938385,"first_indexed_time":1406750457,"http_code":200,"src_unparsed":"org,wikipedia!en,\/wiki\/Arrhythmia s443","src_root_hash":"17790707453426894952","history_drop_reason":null,"meta_title":"Arrhythmia - Wikipedia","meta_descriptions":[],"attrs_boilerpipe_text":"Arrhythmia\nOther names\nCardiac arrhythmia, heart arrhythmia, dysrhythmia, irregular heartbeat\nVentricular fibrillation\n(VF) showing disorganized electrical activity producing a spiked tracing on an\nelectrocardiogram\n(ECG)\nSpecialty\nCardiology\nSymptoms\nPalpitations\n,\ndizziness\nor\nlightheadedness\n,\npassing out\n,\nshortness of breath\n,\nchest pain\n,\n[\n1\n]\ndecreased level of consciousness\nComplications\nStroke\n,\nheart failure\n[\n2\n]\n[\n3\n]\n,\ncardiac arrest\nUsual onset\nOlder age\n[\n4\n]\nTypes\nExtra beats\n,\nsupraventricular tachycardias\n,\nventricular arrhythmias\n,\nbradyarrhythmias\n[\n3\n]\nCauses\nProblems with the\nelectrical conduction system of the heart\n[\n2\n]\nDiagnostic method\nElectrocardiogram\n,\nHolter monitor\n[\n5\n]\nTreatment\nMedications, medical procedures (\npacemaker\n), surgery\n[\n6\n]\nFrequency\nMillions\n[\n4\n]\nHeart sounds of a girl experiencing arrhythmia after exercising.\nArrhythmias\n, also known as\ncardiac arrhythmias\n, are irregularities in the\nheartbeat\n, including when it is too fast or too slow.\n[\n2\n]\nEssentially, this is anything but\nnormal sinus rhythm\n. A resting\nheart rate\nthat is too fast – above 100 beats per minute in adults – is called\ntachycardia\n, and a resting heart rate that is too slow – below 60 beats per minute – is called\nbradycardia\n.\n[\n2\n]\nSome types of arrhythmias have no\nsymptoms\n.\n[\n1\n]\nSymptoms, when present, may include\npalpitations\nor feeling a pause between heartbeats.\n[\n1\n]\nIn more serious cases, there may be\nlightheadedness\n,\npassing out\n,\nshortness of breath\n,\nchest pain\n, or\ndecreased level of consciousness\n.\n[\n1\n]\nWhile most cases of arrhythmia are not serious, some predispose a person to complications such as\nstroke\nor\nheart failure\n.\n[\n2\n]\n[\n3\n]\nOthers may result in\nsudden death\n.\n[\n3\n]\nArrhythmias are often categorized into four groups:\nextra beats\n,\nsupraventricular tachycardias\n,\nventricular arrhythmias\nand\nbradyarrhythmias\n.\n[\n3\n]\nExtra beats include\npremature atrial contractions\n,\npremature ventricular contractions\nand\npremature junctional contractions\n.\n[\n3\n]\nSupraventricular tachycardias include\natrial fibrillation\n,\natrial flutter\nand\nparoxysmal supraventricular tachycardia\n.\n[\n3\n]\nVentricular arrhythmias include\nventricular fibrillation\nand\nventricular tachycardia\n.\n[\n3\n]\n[\n7\n]\nBradyarrhythmias are due to\nsinus node dysfunction\nor\natrioventricular conduction disturbances\n.\n[\n8\n]\nArrhythmias are due to problems with the\nelectrical conduction system of the heart\n.\n[\n2\n]\nA number of tests can help with diagnosis, including an\nelectrocardiogram\n(ECG) and\nHolter monitor\n.\n[\n5\n]\nMany arrhythmias can be effectively treated.\n[\n2\n]\nTreatments may include medications, medical procedures such as inserting a\npacemaker\n, and surgery.\n[\n6\n]\nMedications for a fast heart rate may include\nbeta blockers\n, or\nantiarrhythmic agents\nsuch as\nprocainamide\n, which attempt to restore a normal heart rhythm.\n[\n6\n]\nThis latter group may have more significant side effects, especially if taken for a long period of time.\n[\n6\n]\nPacemakers are often used for slow heart rates.\n[\n6\n]\nThose with an irregular heartbeat are often treated with\nblood thinners\nto reduce the risk of complications.\n[\n6\n]\nThose who have severe symptoms from an arrhythmia or are medically unstable may receive urgent treatment with a\ncontrolled electric shock\nin the form of\ncardioversion\nor\ndefibrillation\n.\n[\n6\n]\nArrhythmia affects millions of people.\n[\n4\n]\nIn Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population.\n[\n9\n]\nAtrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990.\n[\n10\n]\nHowever, in most recent cases concerning the SARS-CoV‑2 pandemic, cardiac arrhythmias are commonly developed and associated with high morbidity and mortality among patients hospitalized with the COVID-19 infection, due to the infection's ability to cause myocardial injury.\n[\n11\n]\nSudden cardiac death\nis the cause of about half of deaths due to\ncardiovascular disease\nand about 15% of all deaths globally.\n[\n12\n]\nAbout 80% of sudden cardiac death is the result of ventricular arrhythmias.\n[\n12\n]\nArrhythmias may occur at any age but are more common among older people.\n[\n4\n]\nArrhythmias may also occur in children; however, the normal range for the heart rate varies with age.\n[\n3\n]\nBroad classification of arrhythmias according to region of heart required to sustain the rhythm\nArrhythmia may be classified by rate (\ntachycardia\n,\nbradycardia\n), mechanism (automaticity, re-entry, triggered) or duration (isolated\npremature beats\n; couplets; runs, that is 3 or more beats; non-sustained = less than 30 seconds or sustained = over 30 seconds).\n[\ncitation needed\n]\nArrhythmias are also classified by site of origin:\n[\ncitation needed\n]\nSinus bradycardia\nSinus arrhythmia\nSinus tachycardia\nPremature atrial contractions (PACs)\nWandering atrial pacemaker\nAtrial tachycardia\nMultifocal atrial tachycardia\nSupraventricular tachycardia (SVT)\nAtrial flutter\nAtrial fibrillation (Afib)\nAV nodal reentrant tachycardia\nJunctional arrhythmia\n[\nedit\n]\nAV nodal reentrant tachycardia\nJunctional rhythm\nJunctional tachycardia\nPremature junctional contraction\nVentricular arrhythmia\n[\nedit\n]\nPremature ventricular contractions\n(PVCs), sometimes called ventricular extra beats (VEBs)\nPremature ventricular beats occurring after every normal beat are termed\nventricular bigeminy\nPVCs that occur at intervals of 2 normal beats to 1 PVC, or 1 normal beat to 2 PVCs, are termed \"PVCs in trigeminy\"\n[\n13\n]\nGroups of three premature ventricular beats are called triplets and are considered a brief run of\nnon-sustained ventricular tachycardia\n(NSVT); if the grouping lasts for more than 30 seconds, it is considered sustained\nventricular tachycardia\n(VT).\n[\n14\n]\nAccelerated idioventricular rhythm\nMonomorphic ventricular tachycardia\nPolymorphic ventricular tachycardia\nVentricular fibrillation\nTorsades de pointes\nArrhythmogenic right ventricular dysplasia\nRe-entry ventricular arrhythmia\nHeart blocks\nare also known as\nAV\nblocks, because the vast majority of them arise from pathology at the\natrioventricular node\n.  They are the most common causes of bradycardia:\n[\ncitation needed\n]\nFirst-degree heart block\n, which manifests as PR prolongation\nSecond-degree heart block\nType 1 Second degree heart block\n, also known as\nMobitz I\nor\nWenckebach\nType 2 Second degree heart block\n, also known as\nMobitz II\nThird-degree heart block\n, also known as\ncomplete heart block\nFirst, second, and third-degree blocks also can occur at the level of the sinoatrial junction. This is referred to as\nsinoatrial block\ntypically manifesting with various degrees and patterns of\nsinus bradycardia\n.\n[\ncitation needed\n]\nSudden arrhythmic death syndrome\n[\nedit\n]\nSudden arrhythmic death syndrome\n(SADS), is a term used as part of\nsudden unexpected death syndrome\nto describe sudden\ndeath\nbecause of\ncardiac arrest\noccasioned by an arrhythmia in the presence or absence of any structural heart disease on autopsy. The most common cause of sudden death in the US is\ncoronary artery disease\nspecifically because of poor oxygenation of the heart muscle, that is\nmyocardial ischemia\nor a\nheart attack\n[\n15\n]\nApproximately 180,000 to 250,000 people die suddenly of this cause every year in the US. SADS may occur from other causes. There are many inherited conditions and heart diseases that can affect young people which can subsequently cause sudden death without advance symptoms.\n[\n16\n]\nCauses of SADS in young people include\nviral myocarditis\n,\nlong QT syndrome\n,\nBrugada syndrome\n,\nCatecholaminergic polymorphic ventricular tachycardia\n,\nhypertrophic cardiomyopathy\nand\narrhythmogenic right ventricular dysplasia\n.\n[\n17\n]\n[\n18\n]\nArrhythmias may also occur in the\nfetus\n.\n[\n19\n]\nThe normal heart rate of the fetus is between 110 and 160 beats per minute. Any rhythm beyond these limits is abnormal and classed as a fetal arrhythmia. These are mainly the result of premature atrial contractions, usually give no symptoms, and have little consequence. However, around one percent of these will be the result of significant structural damage to the heart.\n[\n19\n]\nThe term cardiac arrhythmia covers a very large number of very different conditions.\n[\ncitation needed\n]\nThe most common symptom of arrhythmia is an awareness of an abnormal heartbeat, called\npalpitations\n. These may be infrequent, frequent, or continuous. Some of these arrhythmias are harmless (though\ndistracting\nfor patients) but some of them predispose to adverse outcomes. Arrhythmias also cause\nchest pain\nand\nshortness of breath\n.\n[\ncitation needed\n]\nSome arrhythmias do not cause symptoms and are not associated with increased mortality.  However, some asymptomatic arrhythmias\nare\nassociated with adverse events.  Examples include a higher risk of blood clotting within the heart and a higher risk of insufficient blood being transported to the heart because of a weak heartbeat. Other increased risks are of\nembolization\nand stroke, heart failure, and sudden cardiac death.\n[\ncitation needed\n]\nIf an arrhythmia results in a heartbeat that is too fast, too slow, or too weak to supply the body's needs, this manifests as lower blood pressure and may cause lightheadedness, dizziness, syncope, loss of consciousness,\ncoma\n,\npersistent vegetative state\n, or brain death due to insufficient supply of blood and oxygen to the brain.\n[\n20\n]\nSome types of arrhythmia result in\ncardiac arrest\n, or sudden death.\n[\ncitation needed\n]\nMedical assessment of the abnormality using an\nelectrocardiogram\nis one way to diagnose and assess the risk of any given arrhythmia.\n[\ncitation needed\n]\nCardiac arrhythmia are caused by one of two major mechanisms.  The first of arrhythmia is a result of enhanced or abnormal\nimpulse\nformation originating at the\npacemaker\nor the\nHis\n-\nPurkinje\nnetwork. The second is due to\nre-entry\nconduction disturbances.\n[\n21\n]\nCardiac arrhythmia is often first detected by simple but nonspecific means:\nauscultation\nof the heartbeat with a\nstethoscope\n, or feeling for peripheral\npulses\n. These cannot usually diagnose specific arrhythmia but can give a general indication of the heart rate and whether it is regular or irregular. Not all the electrical impulses of the heart produce audible or palpable beats; in many cardiac arrhythmias, the premature or abnormal beats do not produce an effective pumping action and are experienced as \"skipped\" beats.\n[\ncitation needed\n]\nThe simplest\nspecific\ndiagnostic test for assessment of heart rhythm is the\nelectrocardiogram\n(abbreviated ECG or EKG).\n[\n22\n]\n[\n23\n]\nA\nHolter monitor\nis an EKG recorded over a 24-hour period, to detect arrhythmias that may happen briefly and unpredictably throughout the day.\n[\ncitation needed\n]\nA more advanced study of the heart's electrical activity can be performed to assess the source of the\naberrant\nheart beats. This can be accomplished in an\nelectrophysiology study\n, an\nendovascular procedure\nthat uses a catheter to \"listen\" to the electrical activity from within the heart, additionally if the source of the arrhythmias is found, often the abnormal cells can be ablated and the arrhythmia can be permanently corrected.\nTransesophageal atrial stimulation\n(TAS) instead uses an electrode inserted through the\nesophagus\nto a part where the distance to the posterior wall of the\nleft atrium\nis only approximately 5–6 mm (remaining constant in people of different age and weight).\n[\n24\n]\nTransesophageal atrial stimulation can differentiate between\natrial flutter\n,\nAV nodal reentrant tachycardia\nand orthodromic\natrioventricular reentrant tachycardia\n.\n[\n25\n]\nIt can also evaluate the risk in people with\nWolff–Parkinson–White syndrome\n, as well as terminate\nsupraventricular tachycardia\ncaused by\nre-entry\n.\n[\n25\n]\nDifferential diagnosis\n[\nedit\n]\nNormal electrical activity\n[\nedit\n]\nEach heartbeat originates as an electrical impulse from a small area of tissue in the right\natrium\nof the heart called the\nsinus node or sinoatrial node (SA node)\n. The impulse initially causes both atria to contract, then activates the\natrioventricular node (AV node)\n, which is normally the only electrical connection between the atria and the\nventricles\n(main pumping chambers).  The impulse then spreads through both ventricles via the\nbundle of His\nand the\nPurkinje fibers\ncausing a synchronized contraction of the heart muscle and, thus, the pulse.\n[\ncitation needed\n]\nIn adults, the normal resting heart rate ranges from 60 to 90 beats per minute. The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered normal.\n[\ncitation needed\n]\nThe term\nsinus arrhythmia\n[\n26\n]\nrefers to a normal phenomenon of alternating mild acceleration and slowing of the heart rate that occurs with breathing in and out respectively.  It is usually quite pronounced in children and steadily decreases with age. This can also be present during\nmeditation\nbreathing exercises that involve deep inhaling and breath holding patterns.\n[\n27\n]\nNormal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm.\nA slow rhythm (less than 60 beats\/min) is labelled\nbradycardia\n. This may be caused by a slowed signal from the sinus node (sinus bradycardia), by a pause in the normal activity of the sinus node (sinus arrest), or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block). Heart block comes in varying degrees and severity. It may be caused by reversible poisoning of the AV node (with drugs that impair conduction) or by irreversible damage to the node. Bradycardias may also be present in the normally functioning heart of endurance athletes or other well-conditioned persons. Bradycardia may also occur in\nsome types of seizures\n.\n[\ncitation needed\n]\nIn adults and children over 15, resting heart rate faster than 100 beats per minute is labeled\ntachycardia\n.  Tachycardia may result in palpitation; however, tachycardia is not\nnecessarily\nan arrhythmia. Increased heart rate is a normal response to physical exercise or emotional stress.  This is mediated by the\nsympathetic nervous system\non the\nsinus node\nand called sinus tachycardia.  Other conditions that increase sympathetic nervous system activity in the heart include ingested or injected substances, such as\ncaffeine\nor\namphetamines\n, and an overactive thyroid gland (\nhyperthyroidism\n) or\nanemia\n.\n[\ncitation needed\n]\nTachycardia that is not sinus tachycardia usually results from the addition of abnormal impulses to the normal\ncardiac cycle\n.  Abnormal impulses can begin by one of three mechanisms: automaticity, re-entry, or triggered activity.  A specialized form of re-entry which is both common and problematic is termed fibrillation.\n[\ncitation needed\n]\nAlthough the term \"tachycardia\" has been known for over 160 years, bases for the classification of arrhythmias are still being discussed.\n[\ncitation needed\n]\nCongenital heart defects are structural or electrical pathway problems in the heart that are present at birth.  Anyone can be affected by this because overall health does not play a role in the problem.  Problems with the electrical pathway of the heart can cause very fast or even deadly arrhythmias.\nWolff–Parkinson–White syndrome\nis due to an extra pathway in the heart that is made up of electrical muscle tissue.  This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly.  Right\nventricular outflow tract\ntachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals.  This defect is due to an electrical node in the right ventricle just before the pulmonary artery.  When the node is stimulated, the patient will go into ventricular tachycardia, which does not allow the heart to fill with blood before beating again.\nLong QT syndrome\nis another complex problem in the heart and has been labeled as an independent factor in mortality.    There are multiple methods of treatment for these including cardiac ablations, medication treatment, or lifestyle changes to have less stress and exercise.\n[\ncitation needed\n]\nAutomaticity refers to a\ncardiac muscle\ncell firing off an impulse on its own.  All of the cells in the heart have the ability to initiate an\naction potential\n; however, only some of these cells are designed to routinely trigger heartbeats.  These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His, and Purkinje fibers.  The\nsinoatrial node\nis a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heartbeat.\n[\ncitation needed\n]\nAny part of the heart that initiates an impulse without waiting for the sinoatrial node is called an\nectopic\nfocus and is, by definition, a pathological phenomenon. This may cause a single premature beat now and then, or, if the\nectopic focus\nfires more often than the sinoatrial node, it can produce a sustained abnormal rhythm. Rhythms produced by an ectopic focus in the atria, or by the\natrioventricular node\n, are the least dangerous dysrhythmias; but they can still produce a decrease in the heart's pumping efficiency because the signal reaches the various parts of the heart muscle with different timing than usual and can be responsible for poorly coordinated contraction.\n[\ncitation needed\n]\nConditions that increase automaticity include\nsympathetic nervous system\nstimulation and\nhypoxia\n. The resulting heart rhythm depends on where the first signal begins: If it is the sinoatrial node, the rhythm remains normal but rapid; if it is an ectopic focus, many types of dysrhythmia may ensue.\nRe-entrant arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping.\n[\n28\n]\n[\n29\n]\nEvery cardiac cell can transmit\nimpulses of excitation\nin every direction but will do so only once within a short time. Normally, the\naction potential\nimpulse will spread through the heart quickly enough that each cell will respond only once.  However, if there is some essential heterogeneity of\nrefractory period\nor if conduction is abnormally slow in some areas (for example in heart damage) so the myocardial cells are unable to activate the fast sodium channel, part of the impulse will arrive late and potentially be treated as a new impulse. Depending on the timing, this can produce a sustained abnormal circuit rhythm.\nAs a sort of\nre-entry\n, vortices of excitation in the myocardium (\nautowave vortices\n) are considered to be the main mechanism of life-threatening cardiac arrhythmias.\n[\n30\n]\nIn particular, the\nautowave reverberator\nis common in the thin walls of the atria, sometimes resulting in\natrial flutter\n. Re-entry is also responsible for most\nparoxysmal supraventricular tachycardia\n, and dangerous\nventricular tachycardia\n. These types of re-entry circuits are different from\nWPW\nsyndromes, which utilize abnormal conduction pathways.\nAlthough\nomega-3 fatty acids\nfrom\nfish oil\ncan be protective against arrhythmias, they can facilitate re-entrant arrhythmias.\n[\n31\n]\nWhen an entire chamber of the heart is involved in multiple micro-re-entry circuits and is, therefore, quivering with chaotic electrical impulses, it is said to be in fibrillation.\nFibrillation can affect the atrium (\natrial fibrillation\n) or the ventricle (\nventricular fibrillation\n): ventricular fibrillation is imminently life-threatening.\nAtrial fibrillation affects the upper chambers of the heart, known as the\natria\n. Atrial fibrillation may be due to serious underlying medical conditions and should be evaluated by a\nphysician\n. It is not typically a medical emergency.\nVentricular fibrillation occurs in the\nventricles\n(lower chambers) of the heart; it is always a medical emergency. If left untreated,\nventricular fibrillation\n(VF, or V-fib) can lead to death within minutes. When a heart goes into V-fib, effective pumping of the blood stops. V-fib is considered a form of\ncardiac arrest\n. An affected individual will not survive unless\ncardiopulmonary resuscitation\n(CPR) and\ndefibrillation\nare provided immediately.\nCPR can prolong the survival of the\nbrain\nin the lack of a normal pulse, but defibrillation is the only intervention that can restore a healthy heart rhythm. Defibrillation is performed by applying an electric shock to the heart, which resets the cells, permitting a normal beat to re-establish itself.\nTriggered beats occur when problems at the level of the ion channels in individual heart cells result in abnormal propagation of electrical activity and can lead to a sustained abnormal rhythm. They are relatively rare and can result from the action of anti-arrhythmic drugs, or after\ndepolarizations\n.\n[\ncitation needed\n]\nThe method of cardiac rhythm management depends firstly on whether the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro- or cryo-cautery.\n[\ncitation needed\n]\nIn the United States, people admitted to the hospital with cardiac arrhythmia and conduction disorders with and without complications were admitted to the intensive care unit more than half the time in 2011.\n[\n32\n]\nSeveral physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node.  This can slow down or stop several arrhythmias that originate above or at the AV node (see main article:\nsupraventricular tachycardias\n).  Parasympathetic nervous supply to the heart is via the\nvagus nerve\n, and these maneuvers are collectively known as\nvagal maneuvers\n.\nAntiarrhythmic drugs\n[\nedit\n]\nThere are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes.  Although the goal of drug therapy is to prevent arrhythmia, nearly every antiarrhythmic drug has the potential to act as a\npro-arrhythmic\n, and so must be carefully selected and used under medical supervision.\nSeveral groups of drugs slow conduction through the heart, without actually preventing an arrhythmia.  These drugs can be used to \"rate control\" a fast rhythm and make it physically tolerable for the patient.\n[\ncitation needed\n]\nSome arrhythmias promote blood clotting within the heart and increase the risk of embolus and stroke.\nAnticoagulant\nmedications such as\nwarfarin\nand\nheparins\n, and anti-platelet drugs such as\naspirin\ncan reduce the risk of clotting.\nArrhythmias may also be treated electrically, by applying a shock across the heart – either externally to the chest wall, or internally to the heart via implanted electrodes.\n[\n33\n]\nCardioversion\nis either achieved pharmacologically or via the application of a shock\nsynchronized\nto the underlying heartbeat.  It is used for the treatment of supraventricular tachycardias. In elective cardioversion, the recipient is usually sedated or lightly\nanesthetized\nfor the procedure.\nDefibrillation\ndiffers in that the shock is not synchronized.  It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, more electricity is required for defibrillation than for cardioversion. In most defibrillation, the recipient has lost consciousness so there is no need for sedation.\nDefibrillation or cardioversion may be accomplished by an\nimplantable cardioverter-defibrillator\n(ICD).\nElectrical treatment of arrhythmias also includes\ncardiac pacing\n. Temporary pacing may be necessary for reversible causes of very slow heartbeats, or\nbradycardia\n(for example, from\ndrug overdose\nor\nmyocardial infarction\n). A permanent\npacemaker\nmay be placed in situations where the bradycardia is not expected to recover.\nSome cardiologists further sub-specialize into electrophysiology.  In specialized\ncatheter laboratories\n, they use fine probes inserted through the blood vessels to map electrical activity from within the heart.  This allows abnormal areas of conduction to be located very accurately and subsequently destroyed by heat, cold, electrical, or laser probes in a process called\ncatheter ablation\n.\nThis procedure may be completely curative for some forms of arrhythmia, but for others, the success rate remains disappointing.\nAV nodal reentrant tachycardia\nis often curable by ablating one of the pathways in the\nAV node\n(usually the slow pathway).\nAtrial fibrillation\ncan also be treated, by performing a\npulmonary vein\nisolation, but the results are less reliable.\nArrhythmias due to medications have been reported since the 1920s with the use of\nquinine\n.\n[\n34\n]\nIn the 1960s and 1970s problems with antihistamines and antipsychotics were discovered.\n[\n34\n]\nIt was not until the 1980s that the underlying issue,\nQTc prolongation\nwas determined.\n[\n34\n]\nOsborn waves\non\nelectrocardiogram\n(\nECG\n) are frequent during\ntargeted temperature management (TTM)\nafter\ncardiac arrest\n, particularly in patients treated with 33 °C.\n[\n35\n]\nOsborn waves\nare not associated with increased risk of\nventricular arrhythmia\n, and may be considered a\nbenign\nphysiological phenomenon, associated with lower\nmortality\nin univariable analyses.\n[\n35\n]\nPre-excitation syndrome\nHoliday heart syndrome\n^\na\nb\nc\nd\n\"What Are the Signs and Symptoms of an Arrhythmia?\"\n. National Heart, Lung, and Blood Institute. July 1, 2011.\nArchived\nfrom the original on 19 February 2015\n. Retrieved\n7 March\n2015\n.\n^\na\nb\nc\nd\ne\nf\ng\n\"What Is Arrhythmia?\"\n.\nNational Heart, Lung, and Blood Institute\n. July 1, 2011. Archived from\nthe original\non 2 March 2015\n. Retrieved\n7 March\n2015\n.\n^\na\nb\nc\nd\ne\nf\ng\nh\ni\n\"Types of Arrhythmia\"\n. National Heart, Lung, and Blood Institute. July 1, 2011. Archived from\nthe original\non 7 June 2015\n. Retrieved\n7 March\n2015\n.\n^\na\nb\nc\nd\n\"Who Is at Risk for an Arrhythmia?\"\n. National Heart, Lung, and Blood Institute. July 1, 2011. Archived from\nthe original\non 3 March 2015\n. Retrieved\n7 March\n2015\n.\n^\na\nb\n\"How Are Arrhythmias Diagnosed?\"\n. National Heart, Lung, and Blood Institute. July 1, 2011. Archived from\nthe original\non 18 February 2015\n. Retrieved\n7 March\n2015\n.\n^\na\nb\nc\nd\ne\nf\ng\n\"How Are Arrhythmias Treated?\"\n. National Heart, Lung, and Blood Institute. July 1, 2011. Archived from\nthe original\non 17 February 2015\n. Retrieved\n7 March\n2015\n.\n^\nMartin CA, Matthews GD, Huang CL (April 2012).\n\"Sudden cardiac death and inherited channelopathy: the basic electrophysiology of the myocyte and myocardium in ion channel disease\"\n.\nHeart\n.\n98\n(7):\n536–\n543.\ndoi\n:\n10.1136\/heartjnl-2011-300953\n.\nPMC\n \n3308472\n.\nPMID\n \n22422742\n.\n^\nVogler J, Breithardt G, Eckardt L (July 2012). \"Bradyarrhythmias and conduction blocks\".\nRevista Espanola de Cardiologia\n.\n65\n(7):\n656–\n667.\ndoi\n:\n10.1016\/j.rec.2012.01.027\n.\nPMID\n \n22627074\n.\nS2CID\n \n18983179\n.\n^\nZoni-Berisso M, Lercari F, Carazza T, Domenicucci S (2014).\n\"Epidemiology of atrial fibrillation: European perspective\"\n.\nClinical Epidemiology\n.\n6\n:\n213–\n220.\ndoi\n:\n10.2147\/CLEP.S47385\n.\nPMC\n \n4064952\n.\nPMID\n \n24966695\n.\n^\nNaghavi M, Wang H, Lozano R, Davis A, Liang X, Zhou M, et al. (GBD 2013 Mortality and Causes of Death Collaborators) (January 2015).\n\"Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013\"\n.\nLancet\n.\n385\n(9963):\n117–\n171.\ndoi\n:\n10.1016\/S0140-6736(14)61682-2\n.\nPMC\n \n4340604\n.\nPMID\n \n25530442\n.\n^\nKuck KH (June 2020).\n\"Arrhythmias and sudden cardiac death in the COVID-19 pandemic\"\n.\nHerz\n.\n45\n(4):\n325–\n326.\ndoi\n:\n10.1007\/s00059-020-04924-0\n.\nPMC\n \n7181098\n.\nPMID\n \n32333026\n.\n^\na\nb\nMehra R (2007). \"Global public health problem of sudden cardiac death\".\nJournal of Electrocardiology\n.\n40\n(6 Suppl):\nS118–\nS122.\ndoi\n:\n10.1016\/j.jelectrocard.2007.06.023\n.\nPMID\n \n17993308\n.\n^\nFarzam K, Richards JR (2022-12-27).\n\"Premature ventricular contraction\"\n. StatPearls.\nPMID\n \n30422584\n.\n^\nWagner GS (2001).\nMarriott's Practical Electrocardiography\n(10th ed.). Philadelphia, PA: Williams & Wilkins.\nISBN\n \n0683307460\n.\n[\npage needed\n]\n^\nZipes DP, Wellens HJ (November 1998).\n\"Sudden cardiac death\"\n.\nCirculation\n.\n98\n(21):\n2334–\n2351.\ndoi\n:\n10.1161\/01.CIR.98.21.2334\n.\nPMID\n \n9826323\n.\n^\nDeo R, Albert CM (January 2012).\n\"Epidemiology and genetics of sudden cardiac death\"\n.\nCirculation\n.\n125\n(4):\n620–\n637.\ndoi\n:\n10.1161\/circulationaha.111.023838\n.\nPMC\n \n3399522\n.\nPMID\n \n22294707\n.\n^\nChugh SS, Reinier K, Teodorescu C, Evanado A, Kehr E, Al Samara M, et al. (2008).\n\"Epidemiology of sudden cardiac death: clinical and research implications\"\n.\nProgress in Cardiovascular Diseases\n.\n51\n(3):\n213–\n228.\ndoi\n:\n10.1016\/j.pcad.2008.06.003\n.\nPMC\n \n2621010\n.\nPMID\n \n19026856\n.\n^\nWinkel BG, Holst AG, Theilade J, Kristensen IB, Thomsen JL, Ottesen GL, et al. (April 2011).\n\"Nationwide study of sudden cardiac death in persons aged 1-35 years\"\n.\nEuropean Heart Journal\n.\n32\n(8):\n983–\n990.\ndoi\n:\n10.1093\/eurheartj\/ehq428\n.\nPMID\n \n21131293\n.\n^\na\nb\nBatra AS, Balaji S (2019).\n\"Fetal arrhythmias: Diagnosis and management\"\n.\nIndian Pacing and Electrophysiology Journal\n.\n19\n(3):\n104–\n109.\ndoi\n:\n10.1016\/j.ipej.2019.02.007\n.\nPMC\n \n6531664\n.\nPMID\n \n30817991\n.\n^\n\"Passing Out (Syncope) Caused by Arrhythmias\"\n. Retrieved\n13 April\n2020\n.\n^\nAntzelevitch C, Burashnikov A (March 2011).\n\"Overview of Basic Mechanisms of Cardiac Arrhythmia\"\n.\nCardiac Electrophysiology Clinics\n.\n3\n(1):\n23–\n45.\ndoi\n:\n10.1016\/j.ccep.2010.10.012\n.\nPMC\n \n3164530\n.\nPMID\n \n21892379\n.\n^\nWillcox ME, Compton SJ, Bardy GH (2021-12-01).\n\"Continuous ECG monitoring versus mobile telemetry: A comparison of arrhythmia diagnostics in human- versus algorithmic-dependent systems\"\n.\nHeart Rhythm O2\n.\n2\n(6, Part A):\n543–\n559.\ndoi\n:\n10.1016\/j.hroo.2021.09.008\n.\nISSN\n \n2666-5018\n.\nPMC\n \n8703156\n.\nPMID\n \n34988499\n.\n^\nKiladze MR, Lyakhova UA, Lyakhov PA, Nagornov NN, Vahabi M (2023).\n\"Multimodal Neural Network for Recognition of Cardiac Arrhythmias Based on 12-Load Electrocardiogram Signals\"\n.\nIEEE Access\n.\n11\n:\n133744–\n133754.\nBibcode\n:\n2023IEEEA..11m3744K\n.\ndoi\n:\n10.1109\/ACCESS.2023.3335176\n.\nISSN\n \n2169-3536\n.\n^\nAnier A, Kaik J, Meigas K (2008). \"Device and methods for performing transesophageal stimulation at reduced pacing current threshold\".\nEstonian Journal of Engineering\n.\n57\n(2): 154.\ndoi\n:\n10.3176\/eng.2008.2.05\n.\nS2CID\n \n42055085\n.\n^\na\nb\nPehrson SM, Blomström-Lundqvist C, Ljungström E, Blomström P (October 1994).\n\"Clinical value of transesophageal atrial stimulation and recording in patients with arrhythmia-related symptoms or documented supraventricular tachycardia--correlation to clinical history and invasive studies\"\n.\nClinical Cardiology\n.\n17\n(10):\n528–\n534.\ndoi\n:\n10.1002\/clc.4960171004\n.\nPMID\n \n8001299\n.\nS2CID\n \n7097362\n.\n^\nYasuma F, Hayano J (February 2004). \"Respiratory sinus arrhythmia: why does the heartbeat synchronize with respiratory rhythm?\".\nChest\n.\n125\n(2):\n683–\n690.\ndoi\n:\n10.1378\/chest.125.2.683\n.\nPMID\n \n14769752\n.\n^\nPeressutti C, Martín-González JM, M García-Manso J, Mesa D (November 2010). \"Heart rate dynamics in different levels of Zen meditation\".\nInternational Journal of Cardiology\n.\n145\n(1):\n142–\n146.\ndoi\n:\n10.1016\/j.ijcard.2009.06.058\n.\nPMID\n \n19631997\n.\n^\nWiener N, Rosenblueth A (July 1946). \"The mathematical formulation of the problem of conduction of impulses in a network of connected excitable elements, specifically in cardiac muscle\".\nArchivos del Instituto de Cardiologia de Mexico\n.\n16\n(3):\n205–\n265.\nPMID\n \n20245817\n.\n^\nAllessie MA\n, Bonke FI, Schopman FJ (August 1976).\n\"Circus movement in rabbit atrial muscle as a mechanism of tachycardia. II. The role of nonuniform recovery of excitability in the occurrence of unidirectional block, as studied with multiple microelectrodes\"\n.\nCirculation Research\n.\n39\n(2):\n168–\n177.\ndoi\n:\n10.1161\/01.RES.39.2.168\n.\nPMID\n \n939001\n.\n^\nMandel WJ, ed. (1995).\nCardiac Arrhythmias: Their Mechanisms, Diagnosis, and Management\n(3 ed.). Lippincott Williams & Wilkins.\nISBN\n \n978-0-397-51185-3\n.\n[\npage needed\n]\n^\nDen Ruijter HM, Berecki G, Opthof T, Verkerk AO, Zock PL, Coronel R (January 2007).\n\"Pro- and antiarrhythmic properties of a diet rich in fish oil\"\n.\nCardiovascular Research\n.\n73\n(2):\n316–\n325.\ndoi\n:\n10.1016\/j.cardiores.2006.06.014\n.\nPMID\n \n16859661\n.\n^\nBarrett ML, Smith MW, Elizhauser A, Honigman LS, Pines JM (December 2014).\n\"Utilization of Intensive Care Services, 2011\"\n.\nHCUP Statistical Brief\n(185). Rockville, MD: Agency for Healthcare Research and Quality.\nPMID\n \n25654157\n.\nArchived\nfrom the original on 2015-04-02.\n^\n\"AED Buyer's Guide | AED Prices & Comparison\"\n.\nAED Brands\n. Retrieved\n2021-08-13\n.\n^\na\nb\nc\nHeist EK, Ruskin JN (October 2010).\n\"Drug-induced arrhythmia\"\n.\nCirculation\n.\n122\n(14):\n1426–\n1435.\ndoi\n:\n10.1161\/circulationaha.109.894725\n.\nPMID\n \n20921449\n.\n^\na\nb\nHadziselimovic E, Thomsen JH, Kjaergaard J, Køber L, Graff C, Pehrson S, et al. (July 2018).\n\"Osborn waves following out-of-hospital cardiac arrest—Effect of level of temperature management and risk of arrhythmia and death\"\n.\nResuscitation\n.\n128\n:\n119–\n125.\ndoi\n:\n10.1016\/j.resuscitation.2018.04.037\n.\nISSN\n \n0300-9572\n.\nPMID\n \n29723608\n.\nS2CID\n \n19236851\n.","attrs_markdown":"[Jump to content](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#bodyContent)\n\nMain menu\n\nMain menu\n\nmove to sidebar\n\nhide\n\nNavigation\n\n- [Main page](https:\/\/en.wikipedia.org\/wiki\/Main_Page \"Visit the main page [z]\")\n- [Contents](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contents \"Guides to browsing Wikipedia\")\n- [Current events](https:\/\/en.wikipedia.org\/wiki\/Portal:Current_events \"Articles related to current events\")\n- [Random article](https:\/\/en.wikipedia.org\/wiki\/Special:Random \"Visit a randomly selected article [x]\")\n- [About Wikipedia](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:About \"Learn about Wikipedia and how it works\")\n- [Contact us](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Contact_us \"How to contact Wikipedia\")\n\nContribute\n\n- [Help](https:\/\/en.wikipedia.org\/wiki\/Help:Contents \"Guidance on how to use and edit Wikipedia\")\n- [Learn to edit](https:\/\/en.wikipedia.org\/wiki\/Help:Introduction \"Learn how to edit Wikipedia\")\n- [Community portal](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Community_portal \"The hub for editors\")\n- [Recent changes](https:\/\/en.wikipedia.org\/wiki\/Special:RecentChanges \"A list of recent changes to Wikipedia [r]\")\n- [Upload file](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:File_upload_wizard \"Add images or other media for use on Wikipedia\")\n- [Special pages](https:\/\/en.wikipedia.org\/wiki\/Special:SpecialPages \"A list of all special pages [q]\")\n\n[![](https:\/\/en.wikipedia.org\/static\/images\/icons\/enwiki-25.svg) ![Wikipedia](https:\/\/en.wikipedia.org\/static\/images\/mobile\/copyright\/wikipedia-wordmark-en-25.svg) ![The Free Encyclopedia](https:\/\/en.wikipedia.org\/static\/images\/mobile\/copyright\/wikipedia-tagline-en-25.svg)](https:\/\/en.wikipedia.org\/wiki\/Main_Page)\n\n[Search](https:\/\/en.wikipedia.org\/wiki\/Special:Search \"Search Wikipedia [f]\")\n\nAppearance\n\n- [Donate](https:\/\/donate.wikimedia.org\/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en)\n- [Create account](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CreateAccount&returnto=Arrhythmia \"You are encouraged to create an account and log in; however, it is not mandatory\")\n- [Log in](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UserLogin&returnto=Arrhythmia \"You're encouraged to log in; however, it's not mandatory. [o]\")\n\nPersonal tools\n\n- [Donate](https:\/\/donate.wikimedia.org\/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en)\n- [Create account](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CreateAccount&returnto=Arrhythmia \"You are encouraged to create an account and log in; however, it is not mandatory\")\n- [Log in](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UserLogin&returnto=Arrhythmia \"You're encouraged to log in; however, it's not mandatory. [o]\")\n\n## Contents\nmove to sidebar\n\nhide\n\n- [(Top)](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia)\n- [1 Classification](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Classification)\n  Toggle Classification subsection\n  - [1\\.1 Atrial arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Atrial_arrhythmia)\n  - [1\\.2 Junctional arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Junctional_arrhythmia)\n  - [1\\.3 Ventricular arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Ventricular_arrhythmia)\n  - [1\\.4 Heart blocks](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Heart_blocks)\n  - [1\\.5 Sudden arrhythmic death syndrome](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Sudden_arrhythmic_death_syndrome)\n  - [1\\.6 Fetal arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Fetal_arrhythmia)\n- [2 Signs and symptoms](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Signs_and_symptoms)\n- [3 Mechanism](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Mechanism)\n- [4 Diagnostic](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Diagnostic)\n  Toggle Diagnostic subsection\n  - [4\\.1 Differential diagnosis](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Differential_diagnosis)\n    - [4\\.1.1 Normal electrical activity](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Normal_electrical_activity)\n    - [4\\.1.2 Bradycardias](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Bradycardias)\n    - [4\\.1.3 Tachycardias](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Tachycardias)\n    - [4\\.1.4 Heart defects](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Heart_defects)\n    - [4\\.1.5 Automaticity](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Automaticity)\n    - [4\\.1.6 Re-entry](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Re-entry)\n    - [4\\.1.7 Fibrillation](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Fibrillation)\n    - [4\\.1.8 Triggered beats](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Triggered_beats)\n- [5 Management](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Management)\n  Toggle Management subsection\n  - [5\\.1 Physical maneuvers](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Physical_maneuvers)\n  - [5\\.2 Antiarrhythmic drugs](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Antiarrhythmic_drugs)\n  - [5\\.3 Other drugs](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Other_drugs)\n  - [5\\.4 Electricity](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Electricity)\n  - [5\\.5 Electrical cautery](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Electrical_cautery)\n- [6 Research](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Research)\n- [7 See also](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#See_also)\n- [8 References](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#References)\n- [9 External links](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#External_links)\n\nToggle the table of contents\n\n# Arrhythmia\n70 languages\n\n- [العربية](https:\/\/ar.wikipedia.org\/wiki\/%D8%A7%D8%B6%D8%B7%D8%B1%D8%A7%D8%A8_%D8%A7%D9%84%D9%86%D8%B8%D9%85 \"اضطراب النظم – Arabic\")\n- [Беларуская (тарашкевіца)](https:\/\/be-tarask.wikipedia.org\/wiki\/%D0%90%D1%80%D1%8B%D1%82%D0%BC%D1%96%D1%8F \"Арытмія – Belarusian (Taraškievica orthography)\")\n- [Беларуская](https:\/\/be.wikipedia.org\/wiki\/%D0%90%D1%80%D1%8B%D1%82%D0%BC%D1%96%D1%8F \"Арытмія – Belarusian\")\n- [Български](https:\/\/bg.wikipedia.org\/wiki\/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F \"Аритмия – Bulgarian\")\n- [བོད་ཡིག](https:\/\/bo.wikipedia.org\/wiki\/%E0%BD%A6%E0%BE%99%E0%BD%B2%E0%BD%84%E0%BC%8B%E0%BD%A0%E0%BD%95%E0%BD%A2%E0%BC%8B%E0%BD%A0%E0%BD%86%E0%BD%BC%E0%BD%A3%E0%BC%8B \"སྙིང་འཕར་འཆོལ་ – Tibetan\")\n- [Bosanski](https:\/\/bs.wikipedia.org\/wiki\/Aritmija \"Aritmija – Bosnian\")\n- [Català](https:\/\/ca.wikipedia.org\/wiki\/Arr%C3%ADtmia \"Arrítmia – Catalan\")\n- [کوردی](https:\/\/ckb.wikipedia.org\/wiki\/%D9%84%DB%8E%D8%AF%D8%A7%D9%86%DB%8C_%D8%AF%DA%B5_%D8%A8%DB%95_%D9%86%D8%A7%D8%AA%DB%95%D9%88%D8%A7%D9%88%DB%8C \"لێدانی دڵ بە ناتەواوی – Central Kurdish\")\n- [Čeština](https:\/\/cs.wikipedia.org\/wiki\/Srde%C4%8Dn%C3%AD_arytmie \"Srdeční arytmie – Czech\")\n- [Dansk](https:\/\/da.wikipedia.org\/wiki\/Arytmi \"Arytmi – Danish\")\n- [Deutsch](https:\/\/de.wikipedia.org\/wiki\/Herzrhythmusst%C3%B6rung \"Herzrhythmusstörung – German\")\n- [Ελληνικά](https:\/\/el.wikipedia.org\/wiki\/%CE%91%CF%81%CF%81%CF%85%CE%B8%CE%BC%CE%AF%CE%B1 \"Αρρυθμία – Greek\")\n- [Esperanto](https:\/\/eo.wikipedia.org\/wiki\/Kora_misritmo \"Kora misritmo – Esperanto\")\n- [Español](https:\/\/es.wikipedia.org\/wiki\/Trastorno_del_ritmo_card%C3%ADaco \"Trastorno del ritmo cardíaco – Spanish\")\n- [Eesti](https:\/\/et.wikipedia.org\/wiki\/S%C3%BCdame_r%C3%BCtmih%C3%A4ired \"Südame rütmihäired – Estonian\")\n- [Euskara](https:\/\/eu.wikipedia.org\/wiki\/Arritmia \"Arritmia – Basque\")\n- [فارسی](https:\/\/fa.wikipedia.org\/wiki\/%D8%A2%D8%B1%DB%8C%D8%AA%D9%85%DB%8C_%D9%82%D9%84%D8%A8 \"آریتمی قلب – Persian\")\n- [Suomi](https:\/\/fi.wikipedia.org\/wiki\/Rytmih%C3%A4iri%C3%B6 \"Rytmihäiriö – Finnish\")\n- [Français](https:\/\/fr.wikipedia.org\/wiki\/Trouble_du_rythme_cardiaque \"Trouble du rythme cardiaque – French\")\n- [Gaeilge](https:\/\/ga.wikipedia.org\/wiki\/Neamhrithimeacht \"Neamhrithimeacht – Irish\")\n- [Galego](https:\/\/gl.wikipedia.org\/wiki\/Trastornos_do_ritmo_card%C3%ADaco \"Trastornos do ritmo cardíaco – Galician\")\n- [עברית](https:\/\/he.wikipedia.org\/wiki\/%D7%94%D7%A4%D7%A8%D7%A2%D7%AA_%D7%A7%D7%A6%D7%91 \"הפרעת קצב – Hebrew\")\n- [Hrvatski](https:\/\/hr.wikipedia.org\/wiki\/Aritmija \"Aritmija – Croatian\")\n- [Magyar](https:\/\/hu.wikipedia.org\/wiki\/Sz%C3%ADvritmuszavar \"Szívritmuszavar – Hungarian\")\n- [Հայերեն](https:\/\/hy.wikipedia.org\/wiki\/%D4%B1%D5%BC%D5%AB%D5%A9%D5%B4%D5%AB%D5%A1 \"Առիթմիա – Armenian\")\n- [Bahasa Indonesia](https:\/\/id.wikipedia.org\/wiki\/Aritmia \"Aritmia – Indonesian\")\n- [ГӀалгӀай](https:\/\/inh.wikipedia.org\/wiki\/%D0%94%D0%B5%D0%B3%D0%B0_%D1%85%D0%B0%D1%80%D1%86%D0%B3%D0%B0%D1%80%D1%82 \"Дега харцгарт – Ingush\")\n- [Italiano](https:\/\/it.wikipedia.org\/wiki\/Aritmia \"Aritmia – Italian\")\n- [日本語](https:\/\/ja.wikipedia.org\/wiki\/%E4%B8%8D%E6%95%B4%E8%84%88 \"不整脈 – Japanese\")\n- [ქართული](https:\/\/ka.wikipedia.org\/wiki\/%E1%83%90%E1%83%A0%E1%83%98%E1%83%97%E1%83%9B%E1%83%98%E1%83%90 \"არითმია – Georgian\")\n- [Қазақша](https:\/\/kk.wikipedia.org\/wiki\/%D0%A2%D1%8B%D0%BD%D1%8B%D1%81_%D0%B0%D0%BB%D1%83_%D0%B0%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F%D1%81%D1%8B \"Тыныс алу аритмиясы – Kazakh\")\n- [한국어](https:\/\/ko.wikipedia.org\/wiki\/%EB%B6%80%EC%A0%95%EB%A7%A5 \"부정맥 – Korean\")\n- [Latina](https:\/\/la.wikipedia.org\/wiki\/Arrhythmia_cordis \"Arrhythmia cordis – Latin\")\n- [Lombard](https:\/\/lmo.wikipedia.org\/wiki\/Aritmia \"Aritmia – Lombard\")\n- [Lietuvių](https:\/\/lt.wikipedia.org\/wiki\/Aritmija \"Aritmija – Lithuanian\")\n- [Latviešu](https:\/\/lv.wikipedia.org\/wiki\/Sirds_aritmija \"Sirds aritmija – Latvian\")\n- [മലയാളം](https:\/\/ml.wikipedia.org\/wiki\/%E0%B4%85%E0%B4%A4%E0%B4%BE%E0%B4%B3%E0%B4%A4 \"അതാളത – Malayalam\")\n- [Bahasa Melayu](https:\/\/ms.wikipedia.org\/wiki\/Disritmia_jantung \"Disritmia jantung – Malay\")\n- [Plattdüütsch](https:\/\/nds.wikipedia.org\/wiki\/Hartrhythmusst%C3%B6ren \"Hartrhythmusstören – Low German\")\n- [नेपाल भाषा](https:\/\/new.wikipedia.org\/wiki\/%E0%A4%95%E0%A4%BE%E0%A4%B0%E0%A5%8D%E0%A4%A6%E0%A4%BF%E0%A4%AF%E0%A4%BE%E0%A4%95_%E0%A4%85%E0%A4%B0%E0%A4%BF%E0%A4%A6%E0%A4%AE%E0%A4%BF%E0%A4%AF%E0%A4%BE \"कार्दियाक अरिदमिया – Newari\")\n- [Nederlands](https:\/\/nl.wikipedia.org\/wiki\/Hartritmestoornis \"Hartritmestoornis – Dutch\")\n- [Norsk nynorsk](https:\/\/nn.wikipedia.org\/wiki\/Hjartearytmi \"Hjartearytmi – Norwegian Nynorsk\")\n- [Norsk bokmål](https:\/\/no.wikipedia.org\/wiki\/Arytmi \"Arytmi – Norwegian Bokmål\")\n- [ଓଡ଼ିଆ](https:\/\/or.wikipedia.org\/wiki\/%E0%AC%85%E0%AC%A8%E0%AC%BF%E0%AD%9F%E0%AC%AE%E0%AC%BF%E0%AC%A4_%E0%AC%B9%E0%AD%83%E0%AC%A4%E0%AD%8D_%E0%AC%B8%E0%AD%8D%E0%AC%AA%E0%AC%A8%E0%AD%8D%E0%AC%A6%E0%AC%A8 \"ଅନିୟମିତ ହୃତ୍ ସ୍ପନ୍ଦନ – Odia\")\n- [Kapampangan](https:\/\/pam.wikipedia.org\/wiki\/Cardiac_arrhythmia \"Cardiac arrhythmia – Pampanga\")\n- [Polski](https:\/\/pl.wikipedia.org\/wiki\/Zaburzenia_rytmu_serca \"Zaburzenia rytmu serca – Polish\")\n- [پښتو](https:\/\/ps.wikipedia.org\/wiki\/%D8%AF_%D8%B2%DA%93%D9%87_%D8%A7%D8%B1%DB%90%D8%AA%D9%85%D9%8A%D8%A7 \"د زړه ارېتميا – Pashto\")\n- [Português](https:\/\/pt.wikipedia.org\/wiki\/Arritmia_card%C3%ADaca \"Arritmia cardíaca – Portuguese\")\n- [Română](https:\/\/ro.wikipedia.org\/wiki\/Aritmie_cardiac%C4%83 \"Aritmie cardiacă – Romanian\")\n- [Русский](https:\/\/ru.wikipedia.org\/wiki\/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F_%D1%81%D0%B5%D1%80%D0%B4%D1%86%D0%B0 \"Аритмия сердца – Russian\")\n- [Sicilianu](https:\/\/scn.wikipedia.org\/wiki\/Aritmia \"Aritmia – Sicilian\")\n- [Srpskohrvatski \/ српскохрватски](https:\/\/sh.wikipedia.org\/wiki\/Aritmija \"Aritmija – Serbo-Croatian\")\n- [Simple English](https:\/\/simple.wikipedia.org\/wiki\/Arrhythmia \"Arrhythmia – Simple English\")\n- [Slovenčina](https:\/\/sk.wikipedia.org\/wiki\/Arytmia \"Arytmia – Slovak\")\n- [Slovenščina](https:\/\/sl.wikipedia.org\/wiki\/Sr%C4%8Dna_aritmija \"Srčna aritmija – Slovenian\")\n- [Српски \/ srpski](https:\/\/sr.wikipedia.org\/wiki\/Lupanje_srca \"Lupanje srca – Serbian\")\n- [Svenska](https:\/\/sv.wikipedia.org\/wiki\/Arytmi \"Arytmi – Swedish\")\n- [தமிழ்](https:\/\/ta.wikipedia.org\/wiki\/%E0%AE%87%E0%AE%A4%E0%AE%AF_%E0%AE%87%E0%AE%B2%E0%AE%AF%E0%AE%AE%E0%AE%BF%E0%AE%A9%E0%AF%8D%E0%AE%AE%E0%AF%88 \"இதய இலயமின்மை – Tamil\")\n- [Тоҷикӣ](https:\/\/tg.wikipedia.org\/wiki\/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F%D0%B8_%D0%B4%D0%B8%D0%BB \"Аритмияи дил – Tajik\")\n- [ไทย](https:\/\/th.wikipedia.org\/wiki\/%E0%B8%AB%E0%B8%B1%E0%B8%A7%E0%B9%83%E0%B8%88%E0%B9%80%E0%B8%95%E0%B9%89%E0%B8%99%E0%B8%9C%E0%B8%B4%E0%B8%94%E0%B8%88%E0%B8%B1%E0%B8%87%E0%B8%AB%E0%B8%A7%E0%B8%B0 \"หัวใจเต้นผิดจังหวะ – Thai\")\n- [Türkçe](https:\/\/tr.wikipedia.org\/wiki\/Aritmi \"Aritmi – Turkish\")\n- [Татарча \/ tatarça](https:\/\/tt.wikipedia.org\/wiki\/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F \"Аритмия – Tatar\")\n- [ئۇيغۇرچە \/ Uyghurche](https:\/\/ug.wikipedia.org\/wiki\/%D9%8A%DB%88%D8%B1%DB%95%D9%83_%D8%B1%D9%89%D8%AA%D9%89%D9%85%D8%B3%D9%89%D8%B2%D9%84%D9%89%D9%82%D9%89 \"يۈرەك رىتىمسىزلىقى – Uyghur\")\n- [Українська](https:\/\/uk.wikipedia.org\/wiki\/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D1%96%D1%97_%D1%81%D0%B5%D1%80%D1%86%D1%8F \"Аритмії серця – Ukrainian\")\n- [اردو](https:\/\/ur.wikipedia.org\/wiki\/%D8%A8%DB%92_%D8%A2%DB%81%D9%86%DA%AF%DB%8C \"بے آہنگی – Urdu\")\n- [Oʻzbekcha \/ ўзбекча](https:\/\/uz.wikipedia.org\/wiki\/Aritmiya \"Aritmiya – Uzbek\")\n- [Tiếng Việt](https:\/\/vi.wikipedia.org\/wiki\/R%E1%BB%91i_lo%E1%BA%A1n_nh%E1%BB%8Bp_tim \"Rối loạn nhịp tim – Vietnamese\")\n- [吴语](https:\/\/wuu.wikipedia.org\/wiki\/%E5%BF%83%E5%BE%8B%E5%A4%B1%E5%B8%B8 \"心律失常 – Wu\")\n- [粵語](https:\/\/zh-yue.wikipedia.org\/wiki\/%E5%BF%83%E5%BE%8B%E4%B8%8D%E6%AD%A3 \"心律不正 – Cantonese\")\n- [中文](https:\/\/zh.wikipedia.org\/wiki\/%E5%BF%83%E5%BE%8B%E4%B8%8D%E6%95%B4 \"心律不整 – Chinese\")\n\n[Edit links](https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q189331#sitelinks-wikipedia \"Edit interlanguage links\")\n\n- [Article](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia \"View the content page [c]\")\n- [Talk](https:\/\/en.wikipedia.org\/wiki\/Talk:Arrhythmia \"Discuss improvements to the content page [t]\")\n\nEnglish\n\n- [Read](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia)\n- [Edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit \"Edit this page [e]\")\n- [View history](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=history \"Past revisions of this page [h]\")\n\nTools\n\nTools\n\nmove to sidebar\n\nhide\n\nActions\n\n- [Read](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia)\n- [Edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit \"Edit this page [e]\")\n- [View history](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=history)\n\nGeneral\n\n- [What links here](https:\/\/en.wikipedia.org\/wiki\/Special:WhatLinksHere\/Arrhythmia \"List of all English Wikipedia pages containing links to this page [j]\")\n- [Related changes](https:\/\/en.wikipedia.org\/wiki\/Special:RecentChangesLinked\/Arrhythmia \"Recent changes in pages linked from this page [k]\")\n- [Upload file](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:File_Upload_Wizard \"Upload files [u]\")\n- [Permanent link](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&oldid=1341739168 \"Permanent link to this revision of this page\")\n- [Page information](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=info \"More information about this page\")\n- [Cite this page](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:CiteThisPage&page=Arrhythmia&id=1341739168&wpFormIdentifier=titleform \"Information on how to cite this page\")\n- [Get shortened URL](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FArrhythmia)\n\nPrint\/export\n\n- [Download as PDF](https:\/\/en.wikipedia.org\/w\/index.php?title=Special:DownloadAsPdf&page=Arrhythmia&action=show-download-screen \"Download this page as a PDF file\")\n- [Printable version](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&printable=yes \"Printable version of this page [p]\")\n\nIn other projects\n\n- [Wikimedia Commons](https:\/\/commons.wikimedia.org\/wiki\/Category:Cardiac_arrhythmias)\n- [Wikidata item](https:\/\/www.wikidata.org\/wiki\/Special:EntityPage\/Q189331 \"Structured data on this page hosted by Wikidata [g]\")\n\nAppearance\n\nmove to sidebar\n\nhide\n\nFrom Wikipedia, the free encyclopedia\n\nGroup of medical conditions characterized by irregular heartbeat\n\nThis article is about the irregular heartbeat. For the skin condition, see [erythema](https:\/\/en.wikipedia.org\/wiki\/Erythema \"Erythema\"). For other uses, see [Arrhythmia (disambiguation)](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia_\\(disambiguation\\) \"Arrhythmia (disambiguation)\").\n\nNot to be confused with [Beat deafness](https:\/\/en.wikipedia.org\/wiki\/Beat_deafness \"Beat deafness\").\n\nMedical condition\n\n| Arrhythmia |   |\n|---|---|\n| Other names | Cardiac arrhythmia, heart arrhythmia, dysrhythmia, irregular heartbeat |\n| [![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/f\/f1\/Ventricular_fibrillation.png\/330px-Ventricular_fibrillation.png)](https:\/\/en.wikipedia.org\/wiki\/File:Ventricular_fibrillation.png) |   |\n| [Ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\") (VF) showing disorganized electrical activity producing a spiked tracing on an [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") (ECG) |   |\n| [Specialty](https:\/\/en.wikipedia.org\/wiki\/Medical_specialty \"Medical specialty\") | [Cardiology](https:\/\/en.wikipedia.org\/wiki\/Cardiology \"Cardiology\") |\n| [Symptoms](https:\/\/en.wikipedia.org\/wiki\/Signs_and_symptoms \"Signs and symptoms\") | [Palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitations \"Palpitations\"), [dizziness](https:\/\/en.wikipedia.org\/wiki\/Dizziness \"Dizziness\") or [lightheadedness](https:\/\/en.wikipedia.org\/wiki\/Presyncope \"Presyncope\"), [passing out](https:\/\/en.wikipedia.org\/wiki\/Syncope_\\(medicine\\) \"Syncope (medicine)\"), [shortness of breath](https:\/\/en.wikipedia.org\/wiki\/Shortness_of_breath \"Shortness of breath\"), [chest pain](https:\/\/en.wikipedia.org\/wiki\/Chest_pain \"Chest pain\"),[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) [decreased level of consciousness](https:\/\/en.wikipedia.org\/wiki\/Decreased_level_of_consciousness \"Decreased level of consciousness\") |\n| [Complications](https:\/\/en.wikipedia.org\/wiki\/Complication_\\(medicine\\) \"Complication (medicine)\") | [Stroke](https:\/\/en.wikipedia.org\/wiki\/Stroke \"Stroke\"), [heart failure](https:\/\/en.wikipedia.org\/wiki\/Heart_failure \"Heart failure\")[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2)[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3), [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\") |\n| Usual onset | Older age[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) |\n| Types | [Extra beats](https:\/\/en.wikipedia.org\/wiki\/Premature_heart_beat \"Premature heart beat\"), [supraventricular tachycardias](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\"), [ventricular arrhythmias](https:\/\/en.wikipedia.org\/wiki\/Ventricular_arrhythmia \"Ventricular arrhythmia\"), [bradyarrhythmias](https:\/\/en.wikipedia.org\/wiki\/Bradyarrhythmia \"Bradyarrhythmia\")[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) |\n| [Causes](https:\/\/en.wikipedia.org\/wiki\/Cause_\\(medicine\\) \"Cause (medicine)\") | Problems with the [electrical conduction system of the heart](https:\/\/en.wikipedia.org\/wiki\/Electrical_conduction_system_of_the_heart \"Electrical conduction system of the heart\")[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) |\n| [Diagnostic method](https:\/\/en.wikipedia.org\/wiki\/Medical_diagnosis \"Medical diagnosis\") | [Electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\"), [Holter monitor](https:\/\/en.wikipedia.org\/wiki\/Holter_monitor \"Holter monitor\")[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Diag-5) |\n| Treatment | Medications, medical procedures ([pacemaker](https:\/\/en.wikipedia.org\/wiki\/Pacemaker \"Pacemaker\")), surgery[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) |\n| Frequency | Millions[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) |\n\n![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/8\/87\/Gnome-mime-sound-openclipart.svg\/60px-Gnome-mime-sound-openclipart.svg.png)\n\n[Emma's irregular heartbeat](https:\/\/en.wikipedia.org\/wiki\/File:Emma%27s_irregular_heartbeat.wav \"File:Emma's irregular heartbeat.wav\")\n\nHeart sounds of a girl experiencing arrhythmia after exercising.\n\n***\n*Problems playing this file? See [media help](https:\/\/en.wikipedia.org\/wiki\/Help:Media \"Help:Media\").*\n\n**Arrhythmias**, also known as **cardiac arrhythmias**, are irregularities in the [heartbeat](https:\/\/en.wikipedia.org\/wiki\/Cardiac_cycle \"Cardiac cycle\"), including when it is too fast or too slow.[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) Essentially, this is anything but [normal sinus rhythm](https:\/\/en.wikipedia.org\/wiki\/Normal_sinus_rhythm \"Normal sinus rhythm\"). A resting [heart rate](https:\/\/en.wikipedia.org\/wiki\/Heart_rate \"Heart rate\") that is too fast – above 100 beats per minute in adults – is called [tachycardia](https:\/\/en.wikipedia.org\/wiki\/Tachycardia \"Tachycardia\"), and a resting heart rate that is too slow – below 60 beats per minute – is called [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\").[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) Some types of arrhythmias have no [symptoms](https:\/\/en.wikipedia.org\/wiki\/Symptoms \"Symptoms\").[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) Symptoms, when present, may include [palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitations \"Palpitations\") or feeling a pause between heartbeats.[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) In more serious cases, there may be [lightheadedness](https:\/\/en.wikipedia.org\/wiki\/Presyncope \"Presyncope\"), [passing out](https:\/\/en.wikipedia.org\/wiki\/Syncope_\\(medicine\\) \"Syncope (medicine)\"), [shortness of breath](https:\/\/en.wikipedia.org\/wiki\/Shortness_of_breath \"Shortness of breath\"), [chest pain](https:\/\/en.wikipedia.org\/wiki\/Chest_pain \"Chest pain\"), or [decreased level of consciousness](https:\/\/en.wikipedia.org\/wiki\/Decreased_level_of_consciousness \"Decreased level of consciousness\").[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) While most cases of arrhythmia are not serious, some predispose a person to complications such as [stroke](https:\/\/en.wikipedia.org\/wiki\/Stroke \"Stroke\") or [heart failure](https:\/\/en.wikipedia.org\/wiki\/Heart_failure \"Heart failure\").[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2)[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Others may result in [sudden death](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3)\n\nArrhythmias are often categorized into four groups: [extra beats](https:\/\/en.wikipedia.org\/wiki\/Premature_heart_beat \"Premature heart beat\"), [supraventricular tachycardias](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\"), [ventricular arrhythmias](https:\/\/en.wikipedia.org\/wiki\/Ventricular_arrhythmia \"Ventricular arrhythmia\") and [bradyarrhythmias](https:\/\/en.wikipedia.org\/wiki\/Bradyarrhythmia \"Bradyarrhythmia\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Extra beats include [premature atrial contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_atrial_contraction \"Premature atrial contraction\"), [premature ventricular contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_ventricular_contraction \"Premature ventricular contraction\") and [premature junctional contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_junctional_contractions \"Premature junctional contractions\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Supraventricular tachycardias include [atrial fibrillation](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\"), [atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\") and [paroxysmal supraventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Paroxysmal_supraventricular_tachycardia \"Paroxysmal supraventricular tachycardia\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Ventricular arrhythmias include [ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\") and [ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3)[\\[7\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Martin2012-7) Bradyarrhythmias are due to [sinus node dysfunction](https:\/\/en.wikipedia.org\/wiki\/Sinus_node_dysfunction \"Sinus node dysfunction\") or [atrioventricular conduction disturbances](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_block \"Atrioventricular block\").[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-8) Arrhythmias are due to problems with the [electrical conduction system of the heart](https:\/\/en.wikipedia.org\/wiki\/Electrical_conduction_system_of_the_heart \"Electrical conduction system of the heart\").[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) A number of tests can help with diagnosis, including an [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") (ECG) and [Holter monitor](https:\/\/en.wikipedia.org\/wiki\/Holter_monitor \"Holter monitor\").[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Diag-5)\n\nMany arrhythmias can be effectively treated.[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) Treatments may include medications, medical procedures such as inserting a [pacemaker](https:\/\/en.wikipedia.org\/wiki\/Pacemaker \"Pacemaker\"), and surgery.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Medications for a fast heart rate may include [beta blockers](https:\/\/en.wikipedia.org\/wiki\/Beta_blockers \"Beta blockers\"), or [antiarrhythmic agents](https:\/\/en.wikipedia.org\/wiki\/Antiarrhythmic_agent \"Antiarrhythmic agent\") such as [procainamide](https:\/\/en.wikipedia.org\/wiki\/Procainamide \"Procainamide\"), which attempt to restore a normal heart rhythm.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) This latter group may have more significant side effects, especially if taken for a long period of time.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Pacemakers are often used for slow heart rates.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Those with an irregular heartbeat are often treated with [blood thinners](https:\/\/en.wikipedia.org\/wiki\/Blood_thinner \"Blood thinner\") to reduce the risk of complications.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Those who have severe symptoms from an arrhythmia or are medically unstable may receive urgent treatment with a [controlled electric shock](https:\/\/en.wikipedia.org\/wiki\/Electric_shock#Medical_uses \"Electric shock\") in the form of [cardioversion](https:\/\/en.wikipedia.org\/wiki\/Cardioversion \"Cardioversion\") or [defibrillation](https:\/\/en.wikipedia.org\/wiki\/Defibrillation \"Defibrillation\").[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6)\n\nArrhythmia affects millions of people.[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population.[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Zoni2014-9) Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990.[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-GDB2013-10) However, in most recent cases concerning the SARS-CoV‑2 pandemic, cardiac arrhythmias are commonly developed and associated with high morbidity and mortality among patients hospitalized with the COVID-19 infection, due to the infection's ability to cause myocardial injury.[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-11) [Sudden cardiac death](https:\/\/en.wikipedia.org\/wiki\/Sudden_cardiac_death \"Sudden cardiac death\") is the cause of about half of deaths due to [cardiovascular disease](https:\/\/en.wikipedia.org\/wiki\/Cardiovascular_disease \"Cardiovascular disease\") and about 15% of all deaths globally.[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Meh2007-12) About 80% of sudden cardiac death is the result of ventricular arrhythmias.[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Meh2007-12) Arrhythmias may occur at any age but are more common among older people.[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) Arrhythmias may also occur in children; however, the normal range for the heart rate varies with age.[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3)\n\n## Classification\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=1 \"Edit section: Classification\")\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/7\/77\/De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png\/500px-De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png)](https:\/\/en.wikipedia.org\/wiki\/File:De-Atrial_ventricular_\\(CardioNetworks_ECGpedia\\).png)\n\nBroad classification of arrhythmias according to region of heart required to sustain the rhythm\n\nArrhythmia may be classified by rate ([tachycardia](https:\/\/en.wikipedia.org\/wiki\/Tachycardia \"Tachycardia\"), [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\")), mechanism (automaticity, re-entry, triggered) or duration (isolated [premature beats](https:\/\/en.wikipedia.org\/wiki\/Premature_heart_beat \"Premature heart beat\"); couplets; runs, that is 3 or more beats; non-sustained = less than 30 seconds or sustained = over 30 seconds).\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nArrhythmias are also classified by site of origin:\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n### Atrial arrhythmia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=2 \"Edit section: Atrial arrhythmia\")\\]\n\n- [Sinus bradycardia](https:\/\/en.wikipedia.org\/wiki\/Sinus_bradycardia \"Sinus bradycardia\")\n- [Sinus arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Sinus_arrhythmia \"Sinus arrhythmia\")\n- [Sinus tachycardia](https:\/\/en.wikipedia.org\/wiki\/Sinus_tachycardia \"Sinus tachycardia\")\n- [Premature atrial contractions (PACs)](https:\/\/en.wikipedia.org\/wiki\/Premature_atrial_contraction \"Premature atrial contraction\")\n- [Wandering atrial pacemaker](https:\/\/en.wikipedia.org\/wiki\/Wandering_pacemaker \"Wandering pacemaker\")\n- [Atrial tachycardia](https:\/\/en.wikipedia.org\/wiki\/Atrial_tachycardia \"Atrial tachycardia\")\n- [Multifocal atrial tachycardia](https:\/\/en.wikipedia.org\/wiki\/Multifocal_atrial_tachycardia \"Multifocal atrial tachycardia\")\n- [Supraventricular tachycardia (SVT)](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\")\n- [Atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\")\n- [Atrial fibrillation (Afib)](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\")\n- [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\")\n\n### Junctional arrhythmia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=3 \"Edit section: Junctional arrhythmia\")\\]\n\n- [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\")\n- [Junctional rhythm](https:\/\/en.wikipedia.org\/wiki\/Junctional_rhythm \"Junctional rhythm\")\n- [Junctional tachycardia](https:\/\/en.wikipedia.org\/wiki\/Junctional_tachycardia \"Junctional tachycardia\")\n- [Premature junctional contraction](https:\/\/en.wikipedia.org\/wiki\/Premature_junctional_contraction \"Premature junctional contraction\")\n\n### Ventricular arrhythmia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=4 \"Edit section: Ventricular arrhythmia\")\\]\n\n- [Premature ventricular contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_ventricular_contraction \"Premature ventricular contraction\") (PVCs), sometimes called ventricular extra beats (VEBs)\n  - Premature ventricular beats occurring after every normal beat are termed [ventricular bigeminy](https:\/\/en.wikipedia.org\/wiki\/Ventricular_bigeminy \"Ventricular bigeminy\")\n  - PVCs that occur at intervals of 2 normal beats to 1 PVC, or 1 normal beat to 2 PVCs, are termed \"PVCs in trigeminy\"[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Farzam-13)\n  - Groups of three premature ventricular beats are called triplets and are considered a brief run of [non-sustained ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Non-sustained_ventricular_tachycardia \"Non-sustained ventricular tachycardia\") (NSVT); if the grouping lasts for more than 30 seconds, it is considered sustained [ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\") (VT).[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-wagnerNSVT-14)\n- [Accelerated idioventricular rhythm](https:\/\/en.wikipedia.org\/wiki\/Accelerated_idioventricular_rhythm \"Accelerated idioventricular rhythm\")\n- [Monomorphic ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\")\n- [Polymorphic ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Polymorphic_ventricular_tachycardia \"Polymorphic ventricular tachycardia\")\n- [Ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\")\n- [Torsades de pointes](https:\/\/en.wikipedia.org\/wiki\/Torsades_de_pointes \"Torsades de pointes\")\n- [Arrhythmogenic right ventricular dysplasia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmogenic_right_ventricular_dysplasia \"Arrhythmogenic right ventricular dysplasia\")\n- [Re-entry ventricular arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Re-entry_ventricular_arrhythmia \"Re-entry ventricular arrhythmia\")\n\n### Heart blocks\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=5 \"Edit section: Heart blocks\")\\]\n\n[Heart blocks](https:\/\/en.wikipedia.org\/wiki\/Heart_block \"Heart block\") are also known as [AV](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\") blocks, because the vast majority of them arise from pathology at the [atrioventricular node](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\"). They are the most common causes of bradycardia:\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n- [First-degree heart block](https:\/\/en.wikipedia.org\/wiki\/First-degree_heart_block \"First-degree heart block\"), which manifests as PR prolongation\n- [Second-degree heart block](https:\/\/en.wikipedia.org\/wiki\/Second-degree_heart_block \"Second-degree heart block\")\n  - [Type 1 Second degree heart block](https:\/\/en.wikipedia.org\/wiki\/Type_1_Second_degree_heart_block \"Type 1 Second degree heart block\"), also known as [Mobitz I](https:\/\/en.wikipedia.org\/wiki\/Mobitz_I \"Mobitz I\") or [Wenckebach](https:\/\/en.wikipedia.org\/wiki\/Wenckebach \"Wenckebach\")\n  - [Type 2 Second degree heart block](https:\/\/en.wikipedia.org\/wiki\/Type_2_Second_degree_heart_block \"Type 2 Second degree heart block\"), also known as [Mobitz II](https:\/\/en.wikipedia.org\/wiki\/Mobitz_II \"Mobitz II\")\n- [Third-degree heart block](https:\/\/en.wikipedia.org\/wiki\/Third-degree_heart_block \"Third-degree heart block\"), also known as [complete heart block](https:\/\/en.wikipedia.org\/wiki\/Complete_heart_block \"Complete heart block\")\n\nFirst, second, and third-degree blocks also can occur at the level of the sinoatrial junction. This is referred to as [sinoatrial block](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_block \"Sinoatrial block\") typically manifesting with various degrees and patterns of [sinus bradycardia](https:\/\/en.wikipedia.org\/wiki\/Sinus_bradycardia \"Sinus bradycardia\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n### Sudden arrhythmic death syndrome\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=6 \"Edit section: Sudden arrhythmic death syndrome\")\\]\n\n[Sudden arrhythmic death syndrome](https:\/\/en.wikipedia.org\/wiki\/Sudden_arrhythmic_death_syndrome \"Sudden arrhythmic death syndrome\") (SADS), is a term used as part of *sudden unexpected death syndrome* to describe sudden [death](https:\/\/en.wikipedia.org\/wiki\/Death \"Death\") because of [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\") occasioned by an arrhythmia in the presence or absence of any structural heart disease on autopsy. The most common cause of sudden death in the US is [coronary artery disease](https:\/\/en.wikipedia.org\/wiki\/Coronary_artery_disease \"Coronary artery disease\") specifically because of poor oxygenation of the heart muscle, that is [myocardial ischemia](https:\/\/en.wikipedia.org\/wiki\/Myocardial_ischemia \"Myocardial ischemia\") or a [heart attack](https:\/\/en.wikipedia.org\/wiki\/Myocardial_infarction \"Myocardial infarction\")[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-15) Approximately 180,000 to 250,000 people die suddenly of this cause every year in the US. SADS may occur from other causes. There are many inherited conditions and heart diseases that can affect young people which can subsequently cause sudden death without advance symptoms.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-16)\n\nCauses of SADS in young people include [viral myocarditis](https:\/\/en.wikipedia.org\/wiki\/Viral_myocarditis \"Viral myocarditis\"), [long QT syndrome](https:\/\/en.wikipedia.org\/wiki\/Long_QT_syndrome \"Long QT syndrome\"), [Brugada syndrome](https:\/\/en.wikipedia.org\/wiki\/Brugada_syndrome \"Brugada syndrome\"), [Catecholaminergic polymorphic ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Catecholaminergic_polymorphic_ventricular_tachycardia \"Catecholaminergic polymorphic ventricular tachycardia\"), [hypertrophic cardiomyopathy](https:\/\/en.wikipedia.org\/wiki\/Hypertrophic_cardiomyopathy \"Hypertrophic cardiomyopathy\") and [arrhythmogenic right ventricular dysplasia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmogenic_right_ventricular_dysplasia \"Arrhythmogenic right ventricular dysplasia\").[\\[17\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Chugh-2008-17)[\\[18\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-18)\n\n### Fetal arrhythmia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=7 \"Edit section: Fetal arrhythmia\")\\]\n\nArrhythmias may also occur in the [fetus](https:\/\/en.wikipedia.org\/wiki\/Fetus \"Fetus\").[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Batra-19) The normal heart rate of the fetus is between 110 and 160 beats per minute. Any rhythm beyond these limits is abnormal and classed as a fetal arrhythmia. These are mainly the result of premature atrial contractions, usually give no symptoms, and have little consequence. However, around one percent of these will be the result of significant structural damage to the heart.[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Batra-19)\n\n## Signs and symptoms\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=8 \"Edit section: Signs and symptoms\")\\]\n\nThe term cardiac arrhythmia covers a very large number of very different conditions.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nThe most common symptom of arrhythmia is an awareness of an abnormal heartbeat, called [palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitation \"Palpitation\"). These may be infrequent, frequent, or continuous. Some of these arrhythmias are harmless (though [distracting](https:\/\/en.wikipedia.org\/wiki\/Distracting \"Distracting\") for patients) but some of them predispose to adverse outcomes. Arrhythmias also cause [chest pain](https:\/\/en.wikipedia.org\/wiki\/Chest_pain \"Chest pain\") and [shortness of breath](https:\/\/en.wikipedia.org\/wiki\/Shortness_of_breath \"Shortness of breath\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nSome arrhythmias do not cause symptoms and are not associated with increased mortality. However, some asymptomatic arrhythmias *are* associated with adverse events. Examples include a higher risk of blood clotting within the heart and a higher risk of insufficient blood being transported to the heart because of a weak heartbeat. Other increased risks are of [embolization](https:\/\/en.wikipedia.org\/wiki\/Embolization \"Embolization\") and stroke, heart failure, and sudden cardiac death.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIf an arrhythmia results in a heartbeat that is too fast, too slow, or too weak to supply the body's needs, this manifests as lower blood pressure and may cause lightheadedness, dizziness, syncope, loss of consciousness, [coma](https:\/\/en.wikipedia.org\/wiki\/Coma \"Coma\"), [persistent vegetative state](https:\/\/en.wikipedia.org\/wiki\/Persistent_vegetative_state \"Persistent vegetative state\"), or brain death due to insufficient supply of blood and oxygen to the brain.[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-20)\n\nSome types of arrhythmia result in [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\"), or sudden death.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nMedical assessment of the abnormality using an [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") is one way to diagnose and assess the risk of any given arrhythmia.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n## Mechanism\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=9 \"Edit section: Mechanism\")\\]\n\nCardiac arrhythmia are caused by one of two major mechanisms. The first of arrhythmia is a result of enhanced or abnormal [impulse](https:\/\/en.wikipedia.org\/wiki\/Cardiac_action_potential \"Cardiac action potential\") formation originating at the [pacemaker](https:\/\/en.wikipedia.org\/wiki\/Cardiac_pacemaker \"Cardiac pacemaker\") or the [His](https:\/\/en.wikipedia.org\/wiki\/Bundle_of_His \"Bundle of His\")\\-[Purkinje](https:\/\/en.wikipedia.org\/wiki\/Purkinje_fibers \"Purkinje fibers\") network. The second is due to [re-entry](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Re-entry) conduction disturbances.[\\[21\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Antzelevitch_2011-21)\n\n## Diagnostic\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=10 \"Edit section: Diagnostic\")\\]\n\nCardiac arrhythmia is often first detected by simple but nonspecific means: [auscultation](https:\/\/en.wikipedia.org\/wiki\/Auscultation \"Auscultation\") of the heartbeat with a [stethoscope](https:\/\/en.wikipedia.org\/wiki\/Stethoscope \"Stethoscope\"), or feeling for peripheral [pulses](https:\/\/en.wikipedia.org\/wiki\/Pulse \"Pulse\"). These cannot usually diagnose specific arrhythmia but can give a general indication of the heart rate and whether it is regular or irregular. Not all the electrical impulses of the heart produce audible or palpable beats; in many cardiac arrhythmias, the premature or abnormal beats do not produce an effective pumping action and are experienced as \"skipped\" beats.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nThe simplest *specific* diagnostic test for assessment of heart rhythm is the [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") (abbreviated ECG or EKG).[\\[22\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-22)[\\[23\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-23) A [Holter monitor](https:\/\/en.wikipedia.org\/wiki\/Holter_monitor \"Holter monitor\") is an EKG recorded over a 24-hour period, to detect arrhythmias that may happen briefly and unpredictably throughout the day.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nA more advanced study of the heart's electrical activity can be performed to assess the source of the [aberrant](https:\/\/en.wikipedia.org\/wiki\/Cardiac_aberration \"Cardiac aberration\") heart beats. This can be accomplished in an [electrophysiology study](https:\/\/en.wikipedia.org\/wiki\/Electrophysiology_study \"Electrophysiology study\"), an [endovascular procedure](https:\/\/en.wikipedia.org\/wiki\/Endovascular_procedure \"Endovascular procedure\") that uses a catheter to \"listen\" to the electrical activity from within the heart, additionally if the source of the arrhythmias is found, often the abnormal cells can be ablated and the arrhythmia can be permanently corrected. *Transesophageal atrial stimulation* (TAS) instead uses an electrode inserted through the [esophagus](https:\/\/en.wikipedia.org\/wiki\/Esophagus \"Esophagus\") to a part where the distance to the posterior wall of the [left atrium](https:\/\/en.wikipedia.org\/wiki\/Left_atrium \"Left atrium\") is only approximately 5–6 mm (remaining constant in people of different age and weight).[\\[24\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-MeigasKaik2008-24) Transesophageal atrial stimulation can differentiate between [atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\"), [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\") and orthodromic [atrioventricular reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_reentrant_tachycardia \"Atrioventricular reentrant tachycardia\").[\\[25\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25) It can also evaluate the risk in people with [Wolff–Parkinson–White syndrome](https:\/\/en.wikipedia.org\/wiki\/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome \"Wolff–Parkinson–White syndrome\"), as well as terminate [supraventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\") caused by [re-entry](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrhythmia#Re-entry \"Cardiac arrhythmia\").[\\[25\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25)\n\n### Differential diagnosis\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=11 \"Edit section: Differential diagnosis\")\\]\n\n#### Normal electrical activity\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=12 \"Edit section: Normal electrical activity\")\\]\n\nMain article: [Electrical conduction system of the heart](https:\/\/en.wikipedia.org\/wiki\/Electrical_conduction_system_of_the_heart \"Electrical conduction system of the heart\")\n\nEach heartbeat originates as an electrical impulse from a small area of tissue in the right [atrium](https:\/\/en.wikipedia.org\/wiki\/Atrium_\\(heart\\) \"Atrium (heart)\") of the heart called the [sinus node or sinoatrial node (SA node)](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_node \"Sinoatrial node\"). The impulse initially causes both atria to contract, then activates the [atrioventricular node (AV node)](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\"), which is normally the only electrical connection between the atria and the [ventricles](https:\/\/en.wikipedia.org\/wiki\/Ventricle_\\(heart\\) \"Ventricle (heart)\") (main pumping chambers). The impulse then spreads through both ventricles via the [bundle of His](https:\/\/en.wikipedia.org\/wiki\/Bundle_of_His \"Bundle of His\") and the [Purkinje fibers](https:\/\/en.wikipedia.org\/wiki\/Purkinje_fibers \"Purkinje fibers\") causing a synchronized contraction of the heart muscle and, thus, the pulse.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIn adults, the normal resting heart rate ranges from 60 to 90 beats per minute. The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered normal.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nThe term [sinus arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Respiratory_sinus_arrhythmia \"Respiratory sinus arrhythmia\")[\\[26\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-26) refers to a normal phenomenon of alternating mild acceleration and slowing of the heart rate that occurs with breathing in and out respectively. It is usually quite pronounced in children and steadily decreases with age. This can also be present during [meditation](https:\/\/en.wikipedia.org\/wiki\/Meditation \"Meditation\") breathing exercises that involve deep inhaling and breath holding patterns.[\\[27\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-27)\n\n#### Bradycardias\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=13 \"Edit section: Bradycardias\")\\]\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/1\/1f\/Sinus_pause.PNG\/250px-Sinus_pause.PNG)](https:\/\/en.wikipedia.org\/wiki\/File:Sinus_pause.PNG)\n\nNormal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm.\n\nA slow rhythm (less than 60 beats\/min) is labelled [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\"). This may be caused by a slowed signal from the sinus node (sinus bradycardia), by a pause in the normal activity of the sinus node (sinus arrest), or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block). Heart block comes in varying degrees and severity. It may be caused by reversible poisoning of the AV node (with drugs that impair conduction) or by irreversible damage to the node. Bradycardias may also be present in the normally functioning heart of endurance athletes or other well-conditioned persons. Bradycardia may also occur in [some types of seizures](https:\/\/en.wikipedia.org\/wiki\/Ictal_bradycardia \"Ictal bradycardia\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n#### Tachycardias\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=14 \"Edit section: Tachycardias\")\\]\n\nIn adults and children over 15, resting heart rate faster than 100 beats per minute is labeled [tachycardia](https:\/\/en.wikipedia.org\/wiki\/Tachycardia \"Tachycardia\"). Tachycardia may result in palpitation; however, tachycardia is not *necessarily* an arrhythmia. Increased heart rate is a normal response to physical exercise or emotional stress. This is mediated by the [sympathetic nervous system](https:\/\/en.wikipedia.org\/wiki\/Sympathetic_nervous_system \"Sympathetic nervous system\") on the [sinus node](https:\/\/en.wikipedia.org\/wiki\/Sinus_node \"Sinus node\") and called sinus tachycardia. Other conditions that increase sympathetic nervous system activity in the heart include ingested or injected substances, such as [caffeine](https:\/\/en.wikipedia.org\/wiki\/Caffeine \"Caffeine\") or [amphetamines](https:\/\/en.wikipedia.org\/wiki\/Amphetamines \"Amphetamines\"), and an overactive thyroid gland ([hyperthyroidism](https:\/\/en.wikipedia.org\/wiki\/Hyperthyroidism \"Hyperthyroidism\")) or [anemia](https:\/\/en.wikipedia.org\/wiki\/Anemia \"Anemia\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nTachycardia that is not sinus tachycardia usually results from the addition of abnormal impulses to the normal [cardiac cycle](https:\/\/en.wikipedia.org\/wiki\/Cardiac_cycle \"Cardiac cycle\"). Abnormal impulses can begin by one of three mechanisms: automaticity, re-entry, or triggered activity. A specialized form of re-entry which is both common and problematic is termed fibrillation.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nAlthough the term \"tachycardia\" has been known for over 160 years, bases for the classification of arrhythmias are still being discussed.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n#### Heart defects\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=15 \"Edit section: Heart defects\")\\]\n\nCongenital heart defects are structural or electrical pathway problems in the heart that are present at birth. Anyone can be affected by this because overall health does not play a role in the problem. Problems with the electrical pathway of the heart can cause very fast or even deadly arrhythmias. [Wolff–Parkinson–White syndrome](https:\/\/en.wikipedia.org\/wiki\/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome \"Wolff–Parkinson–White syndrome\") is due to an extra pathway in the heart that is made up of electrical muscle tissue. This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly. Right [ventricular outflow tract](https:\/\/en.wikipedia.org\/wiki\/Ventricular_outflow_tract \"Ventricular outflow tract\") tachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals. This defect is due to an electrical node in the right ventricle just before the pulmonary artery. When the node is stimulated, the patient will go into ventricular tachycardia, which does not allow the heart to fill with blood before beating again. [Long QT syndrome](https:\/\/en.wikipedia.org\/wiki\/Long_QT_syndrome \"Long QT syndrome\") is another complex problem in the heart and has been labeled as an independent factor in mortality. There are multiple methods of treatment for these including cardiac ablations, medication treatment, or lifestyle changes to have less stress and exercise.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n#### Automaticity\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=16 \"Edit section: Automaticity\")\\]\n\nMain article: [Automatic tachycardia](https:\/\/en.wikipedia.org\/wiki\/Automatic_tachycardia \"Automatic tachycardia\")\n\nAutomaticity refers to a [cardiac muscle](https:\/\/en.wikipedia.org\/wiki\/Cardiac_muscle \"Cardiac muscle\") cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an [action potential](https:\/\/en.wikipedia.org\/wiki\/Action_potential \"Action potential\"); however, only some of these cells are designed to routinely trigger heartbeats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His, and Purkinje fibers. The [sinoatrial node](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_node \"Sinoatrial node\") is a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heartbeat.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nAny part of the heart that initiates an impulse without waiting for the sinoatrial node is called an [ectopic](https:\/\/en.wikipedia.org\/wiki\/Cardiac_ectopy \"Cardiac ectopy\") focus and is, by definition, a pathological phenomenon. This may cause a single premature beat now and then, or, if the [ectopic focus](https:\/\/en.wikipedia.org\/wiki\/Ectopic_focus \"Ectopic focus\") fires more often than the sinoatrial node, it can produce a sustained abnormal rhythm. Rhythms produced by an ectopic focus in the atria, or by the [atrioventricular node](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\"), are the least dangerous dysrhythmias; but they can still produce a decrease in the heart's pumping efficiency because the signal reaches the various parts of the heart muscle with different timing than usual and can be responsible for poorly coordinated contraction.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nConditions that increase automaticity include [sympathetic nervous system](https:\/\/en.wikipedia.org\/wiki\/Sympathetic_nervous_system \"Sympathetic nervous system\") stimulation and [hypoxia](https:\/\/en.wikipedia.org\/wiki\/Hypoxia_\\(medical\\) \"Hypoxia (medical)\"). The resulting heart rhythm depends on where the first signal begins: If it is the sinoatrial node, the rhythm remains normal but rapid; if it is an ectopic focus, many types of dysrhythmia may ensue.\n\n#### Re-entry\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=17 \"Edit section: Re-entry\")\\]\n\nRe-entrant arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping.[\\[28\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Wiener-1946-28)[\\[29\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Allessie-1976-29)\n\nEvery cardiac cell can transmit [impulses of excitation](https:\/\/en.wikipedia.org\/wiki\/Autowave \"Autowave\") in every direction but will do so only once within a short time. Normally, the [action potential](https:\/\/en.wikipedia.org\/wiki\/Action_potential \"Action potential\") impulse will spread through the heart quickly enough that each cell will respond only once. However, if there is some essential heterogeneity of [refractory period](https:\/\/en.wikipedia.org\/wiki\/Refractory_period_\\(physiology\\) \"Refractory period (physiology)\") or if conduction is abnormally slow in some areas (for example in heart damage) so the myocardial cells are unable to activate the fast sodium channel, part of the impulse will arrive late and potentially be treated as a new impulse. Depending on the timing, this can produce a sustained abnormal circuit rhythm.\n\nAs a sort of *re-entry*, vortices of excitation in the myocardium ([autowave vortices](https:\/\/en.wikipedia.org\/wiki\/Autowave \"Autowave\")) are considered to be the main mechanism of life-threatening cardiac arrhythmias.[\\[30\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-b-Mandel-1995-30) In particular, the [autowave reverberator](https:\/\/en.wikipedia.org\/wiki\/Autowave_reverberator \"Autowave reverberator\") is common in the thin walls of the atria, sometimes resulting in [atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\"). Re-entry is also responsible for most [paroxysmal supraventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Paroxysmal_supraventricular_tachycardia \"Paroxysmal supraventricular tachycardia\"), and dangerous [ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\"). These types of re-entry circuits are different from [WPW](https:\/\/en.wikipedia.org\/wiki\/WPW \"WPW\") syndromes, which utilize abnormal conduction pathways.\n\nAlthough [omega-3 fatty acids](https:\/\/en.wikipedia.org\/wiki\/Omega-3_fatty_acid \"Omega-3 fatty acid\") from [fish oil](https:\/\/en.wikipedia.org\/wiki\/Fish_oil \"Fish oil\") can be protective against arrhythmias, they can facilitate re-entrant arrhythmias.[\\[31\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Coronel-2007-31)\n\n#### Fibrillation\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=18 \"Edit section: Fibrillation\")\\]\n\nWhen an entire chamber of the heart is involved in multiple micro-re-entry circuits and is, therefore, quivering with chaotic electrical impulses, it is said to be in fibrillation.\n\nFibrillation can affect the atrium ([atrial fibrillation](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\")) or the ventricle ([ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\")): ventricular fibrillation is imminently life-threatening.\n\n- Atrial fibrillation affects the upper chambers of the heart, known as the [atria](https:\/\/en.wikipedia.org\/wiki\/Atrium_\\(heart\\) \"Atrium (heart)\"). Atrial fibrillation may be due to serious underlying medical conditions and should be evaluated by a [physician](https:\/\/en.wikipedia.org\/wiki\/Physician \"Physician\"). It is not typically a medical emergency.\n- Ventricular fibrillation occurs in the [ventricles](https:\/\/en.wikipedia.org\/wiki\/Ventricle_\\(heart\\) \"Ventricle (heart)\") (lower chambers) of the heart; it is always a medical emergency. If left untreated, [ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\") (VF, or V-fib) can lead to death within minutes. When a heart goes into V-fib, effective pumping of the blood stops. V-fib is considered a form of [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\"). An affected individual will not survive unless [cardiopulmonary resuscitation](https:\/\/en.wikipedia.org\/wiki\/Cardiopulmonary_resuscitation \"Cardiopulmonary resuscitation\") (CPR) and [defibrillation](https:\/\/en.wikipedia.org\/wiki\/Defibrillation \"Defibrillation\") are provided immediately.\n\nCPR can prolong the survival of the [brain](https:\/\/en.wikipedia.org\/wiki\/Brain \"Brain\") in the lack of a normal pulse, but defibrillation is the only intervention that can restore a healthy heart rhythm. Defibrillation is performed by applying an electric shock to the heart, which resets the cells, permitting a normal beat to re-establish itself.\n\n#### Triggered beats\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=19 \"Edit section: Triggered beats\")\\]\n\nTriggered beats occur when problems at the level of the ion channels in individual heart cells result in abnormal propagation of electrical activity and can lead to a sustained abnormal rhythm. They are relatively rare and can result from the action of anti-arrhythmic drugs, or after [depolarizations](https:\/\/en.wikipedia.org\/wiki\/Depolarization \"Depolarization\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n## Management\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=20 \"Edit section: Management\")\\]\n\nThe method of cardiac rhythm management depends firstly on whether the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro- or cryo-cautery.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIn the United States, people admitted to the hospital with cardiac arrhythmia and conduction disorders with and without complications were admitted to the intensive care unit more than half the time in 2011.[\\[32\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-32)\n\n### Physical maneuvers\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=21 \"Edit section: Physical maneuvers\")\\]\n\nSeveral physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop several arrhythmias that originate above or at the AV node (see main article: [supraventricular tachycardias](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\")). Parasympathetic nervous supply to the heart is via the [vagus nerve](https:\/\/en.wikipedia.org\/wiki\/Vagus_nerve \"Vagus nerve\"), and these maneuvers are collectively known as [vagal maneuvers](https:\/\/en.wikipedia.org\/wiki\/Vagal_maneuver \"Vagal maneuver\").\n\n### Antiarrhythmic drugs\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=22 \"Edit section: Antiarrhythmic drugs\")\\]\n\nMain article: [Antiarrhythmic agents](https:\/\/en.wikipedia.org\/wiki\/Antiarrhythmic_agents \"Antiarrhythmic agents\")\n\nThere are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes. Although the goal of drug therapy is to prevent arrhythmia, nearly every antiarrhythmic drug has the potential to act as a [pro-arrhythmic](https:\/\/en.wikipedia.org\/wiki\/Pro-arrhythmic \"Pro-arrhythmic\"), and so must be carefully selected and used under medical supervision.\n\n### Other drugs\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=23 \"Edit section: Other drugs\")\\]\n\nSeveral groups of drugs slow conduction through the heart, without actually preventing an arrhythmia. These drugs can be used to \"rate control\" a fast rhythm and make it physically tolerable for the patient.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nSome arrhythmias promote blood clotting within the heart and increase the risk of embolus and stroke. [Anticoagulant](https:\/\/en.wikipedia.org\/wiki\/Anticoagulant \"Anticoagulant\") medications such as [warfarin](https:\/\/en.wikipedia.org\/wiki\/Warfarin \"Warfarin\") and [heparins](https:\/\/en.wikipedia.org\/wiki\/Heparin \"Heparin\"), and anti-platelet drugs such as [aspirin](https:\/\/en.wikipedia.org\/wiki\/Aspirin \"Aspirin\") can reduce the risk of clotting.\n\n### Electricity\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=24 \"Edit section: Electricity\")\\]\n\nArrhythmias may also be treated electrically, by applying a shock across the heart – either externally to the chest wall, or internally to the heart via implanted electrodes.[\\[33\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-33)\n\n[Cardioversion](https:\/\/en.wikipedia.org\/wiki\/Cardioversion \"Cardioversion\") is either achieved pharmacologically or via the application of a shock *synchronized* to the underlying heartbeat. It is used for the treatment of supraventricular tachycardias. In elective cardioversion, the recipient is usually sedated or lightly [anesthetized](https:\/\/en.wikipedia.org\/wiki\/Anesthesia \"Anesthesia\") for the procedure.\n\n[Defibrillation](https:\/\/en.wikipedia.org\/wiki\/Defibrillation \"Defibrillation\") differs in that the shock is not synchronized. It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, more electricity is required for defibrillation than for cardioversion. In most defibrillation, the recipient has lost consciousness so there is no need for sedation.\n\nDefibrillation or cardioversion may be accomplished by an [implantable cardioverter-defibrillator](https:\/\/en.wikipedia.org\/wiki\/Implantable_cardioverter-defibrillator \"Implantable cardioverter-defibrillator\") (ICD).\n\nElectrical treatment of arrhythmias also includes [cardiac pacing](https:\/\/en.wikipedia.org\/wiki\/Cardiac_pacing \"Cardiac pacing\"). Temporary pacing may be necessary for reversible causes of very slow heartbeats, or [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\") (for example, from [drug overdose](https:\/\/en.wikipedia.org\/wiki\/Drug_overdose \"Drug overdose\") or [myocardial infarction](https:\/\/en.wikipedia.org\/wiki\/Myocardial_infarction \"Myocardial infarction\")). A permanent [pacemaker](https:\/\/en.wikipedia.org\/wiki\/Artificial_pacemaker \"Artificial pacemaker\") may be placed in situations where the bradycardia is not expected to recover.\n\n### Electrical cautery\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=25 \"Edit section: Electrical cautery\")\\]\n\nSome cardiologists further sub-specialize into electrophysiology. In specialized [catheter laboratories](https:\/\/en.wikipedia.org\/wiki\/Catheter \"Catheter\"), they use fine probes inserted through the blood vessels to map electrical activity from within the heart. This allows abnormal areas of conduction to be located very accurately and subsequently destroyed by heat, cold, electrical, or laser probes in a process called [catheter ablation](https:\/\/en.wikipedia.org\/wiki\/Catheter_ablation \"Catheter ablation\").\n\nThis procedure may be completely curative for some forms of arrhythmia, but for others, the success rate remains disappointing. [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\") is often curable by ablating one of the pathways in the [AV node](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\") (usually the slow pathway). [Atrial fibrillation](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\") can also be treated, by performing a [pulmonary vein](https:\/\/en.wikipedia.org\/wiki\/Pulmonary_vein \"Pulmonary vein\") isolation, but the results are less reliable.\n\n## Research\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=26 \"Edit section: Research\")\\]\n\nArrhythmias due to medications have been reported since the 1920s with the use of [quinine](https:\/\/en.wikipedia.org\/wiki\/Quinine \"Quinine\").[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Hei2010-34) In the 1960s and 1970s problems with antihistamines and antipsychotics were discovered.[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Hei2010-34) It was not until the 1980s that the underlying issue, [QTc prolongation](https:\/\/en.wikipedia.org\/wiki\/QT_interval#Abnormal_intervals \"QT interval\") was determined.[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Hei2010-34) [Osborn waves](https:\/\/en.wikipedia.org\/wiki\/J_wave \"J wave\") on [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiography \"Electrocardiography\") ([ECG](https:\/\/en.wikipedia.org\/wiki\/ECG \"ECG\")) are frequent during [targeted temperature management (TTM)](https:\/\/en.wikipedia.org\/wiki\/Targeted_temperature_management \"Targeted temperature management\") after [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\"), particularly in patients treated with 33 °C.[\\[35\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-:0-35) [Osborn waves](https:\/\/en.wikipedia.org\/wiki\/J_wave \"J wave\") are not associated with increased risk of [ventricular arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_arrhythmia \"Ventricular arrhythmia\"), and may be considered a [benign](https:\/\/en.wikipedia.org\/wiki\/Benign_early_repolarization \"Benign early repolarization\") physiological phenomenon, associated with lower [mortality](https:\/\/en.wikipedia.org\/wiki\/Mortality_rate \"Mortality rate\") in univariable analyses.[\\[35\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-:0-35)\n\n## See also\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=27 \"Edit section: See also\")\\]\n\n- [Pre-excitation syndrome](https:\/\/en.wikipedia.org\/wiki\/Pre-excitation_syndrome \"Pre-excitation syndrome\")\n- [Holiday heart syndrome](https:\/\/en.wikipedia.org\/wiki\/Holiday_heart_syndrome \"Holiday heart syndrome\")\n\n## References\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=28 \"Edit section: References\")\\]\n\n1. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-3)\n   [\"What Are the Signs and Symptoms of an Arrhythmia?\"](https:\/\/www.nhlbi.nih.gov\/health\/arrhythmias\/symptoms). National Heart, Lung, and Blood Institute. July 1, 2011. [Archived](https:\/\/web.archive.org\/web\/20150219081446\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/signs) from the original on 19 February 2015. Retrieved 7 March 2015.\n2. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-6)\n   [\"What Is Arrhythmia?\"](https:\/\/web.archive.org\/web\/20150302074103\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/). [National Heart, Lung, and Blood Institute](https:\/\/en.wikipedia.org\/wiki\/National_Heart,_Lung,_and_Blood_Institute \"National Heart, Lung, and Blood Institute\"). July 1, 2011. Archived from [the original](http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr) on 2 March 2015. Retrieved 7 March 2015.\n3. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-6) [***h***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-7) [***i***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-8)\n   [\"Types of Arrhythmia\"](https:\/\/web.archive.org\/web\/20150607165144\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/types). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/types) on 7 June 2015. Retrieved 7 March 2015.\n4. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Risk_4-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Risk_4-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Risk_4-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Risk_4-3)\n   [\"Who Is at Risk for an Arrhythmia?\"](https:\/\/web.archive.org\/web\/20150303190136\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/atrisk). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/atrisk) on 3 March 2015. Retrieved 7 March 2015.\n5. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Diag_5-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Diag_5-1)\n   [\"How Are Arrhythmias Diagnosed?\"](https:\/\/web.archive.org\/web\/20150218075708\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/diagnosis). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/diagnosis) on 18 February 2015. Retrieved 7 March 2015.\n6. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-6)\n   [\"How Are Arrhythmias Treated?\"](https:\/\/web.archive.org\/web\/20150217135319\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/treatment). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/treatment) on 17 February 2015. Retrieved 7 March 2015.\n7. **[^](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-Martin2012_7-0)**\n   Martin CA, Matthews GD, Huang CL (April 2012). [\"Sudden cardiac death and inherited channelopathy: the basic electrophysiology of the myocyte and myocardium in ion channel disease\"](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC3308472). *Heart*. **98** (7): 536–543\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1136\/heartjnl-2011-300953](https:\/\/doi.org\/10.1136%2Fheartjnl-2011-300953). [PMC](https:\/\/en.wikipedia.org\/wiki\/PMC_\\(identifier\\) \"PMC (identifier)\") [3308472](https:\/\/www.ncbi.nlm.nih.gov\/pmc\/articles\/PMC3308472). 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[PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [20921449](https:\/\/pubmed.ncbi.nlm.nih.gov\/20921449).\n35. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-:0_35-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-:0_35-1)\n    Hadziselimovic E, Thomsen JH, Kjaergaard J, Køber L, Graff C, Pehrson S, et al. (July 2018). [\"Osborn waves following out-of-hospital cardiac arrest—Effect of level of temperature management and risk of arrhythmia and death\"](https:\/\/doi.org\/10.1016\/j.resuscitation.2018.04.037). *Resuscitation*. **128**: 119–125\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.resuscitation.2018.04.037](https:\/\/doi.org\/10.1016%2Fj.resuscitation.2018.04.037). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [0300-9572](https:\/\/search.worldcat.org\/issn\/0300-9572). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [29723608](https:\/\/pubmed.ncbi.nlm.nih.gov\/29723608). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [19236851](https:\/\/api.semanticscholar.org\/CorpusID:19236851).\n\n## External links\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=29 \"Edit section: External links\")\\]\n\n|   |   |\n|---|---|\n| Classification | [D](https:\/\/www.wikidata.org\/wiki\/Q189331 \"d:Q189331\") **[ICD](https:\/\/en.wikipedia.org\/wiki\/International_Statistical_Classification_of_Diseases_and_Related_Health_Problems \"International Statistical Classification of Diseases and Related Health Problems\")\\-[10](https:\/\/en.wikipedia.org\/wiki\/ICD-10 \"ICD-10\")**: [I47](https:\/\/icd.who.int\/browse10\/2019\/en#\/I47) – [I49](https:\/\/icd.who.int\/browse10\/2019\/en#\/I49) **[ICD](https:\/\/en.wikipedia.org\/wiki\/International_Statistical_Classification_of_Diseases_and_Related_Health_Problems \"International Statistical Classification of Diseases and Related Health Problems\")\\-[9-CM](https:\/\/en.wikipedia.org\/wiki\/List_of_ICD-9_codes \"List of ICD-9 codes\")**: [427](http:\/\/www.icd9data.com\/getICD9Code.ashx?icd9=427) **[MeSH](https:\/\/en.wikipedia.org\/wiki\/Medical_Subject_Headings \"Medical Subject Headings\")**: [D001145](https:\/\/meshb.nlm.nih.gov\/record\/ui?ui=D001145) **[DiseasesDB](https:\/\/en.wikipedia.org\/wiki\/Diseases_Database \"Diseases Database\")**: [15206](http:\/\/www.diseasesdatabase.com\/ddb15206.htm) |\n| External resources | **[MedlinePlus](https:\/\/en.wikipedia.org\/wiki\/MedlinePlus \"MedlinePlus\")**: [001101](https:\/\/www.nlm.nih.gov\/medlineplus\/ency\/article\/001101.htm) |\n\n| [v](https:\/\/en.wikipedia.org\/wiki\/Template:Heart_diseases \"Template:Heart diseases\") [t](https:\/\/en.wikipedia.org\/wiki\/Template_talk:Heart_diseases \"Template talk:Heart diseases\") [e](https:\/\/en.wikipedia.org\/wiki\/Special:EditPage\/Template:Heart_diseases \"Special:EditPage\/Template:Heart diseases\")[Cardiovascular disease](https:\/\/en.wikipedia.org\/wiki\/Cardiovascular_disease \"Cardiovascular disease\") (heart) |   |\n|---|---|\n| [Ischemia](https:\/\/en.wikipedia.org\/wiki\/Ischemia \"Ischemia\") |   |\n|   |   |\n| Coronary disease | [Coronary artery disease](https:\/\/en.wikipedia.org\/wiki\/Coronary_artery_disease \"Coronary artery disease\") (CAD) [Coronary artery aneurysm](https:\/\/en.wikipedia.org\/wiki\/Coronary_artery_aneurysm \"Coronary artery aneurysm\") [Spontaneous coronary artery dissection](https:\/\/en.wikipedia.org\/wiki\/Spontaneous_coronary_artery_dissection \"Spontaneous coronary artery dissection\") (SCAD) [Coronary thrombosis](https:\/\/en.wikipedia.org\/wiki\/Coronary_thrombosis \"Coronary thrombosis\") [Coronary vasospasm](https:\/\/en.wikipedia.org\/wiki\/Coronary_vasospasm \"Coronary vasospasm\") [Myocardial bridge](https:\/\/en.wikipedia.org\/wiki\/Myocardial_bridge \"Myocardial bridge\") |\n| Active ischemia | [Angina pectoris](https:\/\/en.wikipedia.org\/wiki\/Angina \"Angina\") [Prinzmetal's angina](https:\/\/en.wikipedia.org\/wiki\/Prinzmetal%27s_angina \"Prinzmetal's angina\") [Stable angina](https:\/\/en.wikipedia.org\/wiki\/Stable_angina \"Stable angina\") [Acute coronary syndrome](https:\/\/en.wikipedia.org\/wiki\/Acute_coronary_syndrome \"Acute coronary syndrome\") [Myocardial infarction](https:\/\/en.wikipedia.org\/wiki\/Myocardial_infarction \"Myocardial infarction\") [Unstable angina](https:\/\/en.wikipedia.org\/wiki\/Unstable_angina \"Unstable angina\") |\n| [Sequelae](https:\/\/en.wikipedia.org\/wiki\/Myocardial_infarction_complications \"Myocardial infarction complications\") | *hours* [Hibernating myocardium](https:\/\/en.wikipedia.org\/wiki\/Hibernating_myocardium \"Hibernating myocardium\") [Myocardial stunning](https:\/\/en.wikipedia.org\/wiki\/Myocardial_stunning \"Myocardial stunning\") *days* [Myocardial rupture](https:\/\/en.wikipedia.org\/wiki\/Myocardial_rupture \"Myocardial rupture\") *weeks* [Ventricular aneurysm](https:\/\/en.wikipedia.org\/wiki\/Ventricular_aneurysm \"Ventricular aneurysm\") [Dressler syndrome](https:\/\/en.wikipedia.org\/wiki\/Dressler_syndrome \"Dressler syndrome\") |\n| Layers |   |\n|   |   |\n| [Pericardium](https:\/\/en.wikipedia.org\/wiki\/Pericardium \"Pericardium\") | [Pericarditis](https:\/\/en.wikipedia.org\/wiki\/Pericarditis \"Pericarditis\") [Acute](https:\/\/en.wikipedia.org\/wiki\/Acute_pericarditis \"Acute pericarditis\") [Chronic](https:\/\/en.wikipedia.org\/wiki\/Pericarditis#Acute_vs._chronic \"Pericarditis\") \/ [Constrictive](https:\/\/en.wikipedia.org\/wiki\/Constrictive_pericarditis \"Constrictive pericarditis\") [Pericardial effusion](https:\/\/en.wikipedia.org\/wiki\/Pericardial_effusion \"Pericardial effusion\") [Cardiac tamponade](https:\/\/en.wikipedia.org\/wiki\/Cardiac_tamponade \"Cardiac tamponade\") [Hemopericardium](https:\/\/en.wikipedia.org\/wiki\/Hemopericardium \"Hemopericardium\") |\n| [Myocardium](https:\/\/en.wikipedia.org\/wiki\/Cardiac_muscle \"Cardiac muscle\") | [Myocarditis](https:\/\/en.wikipedia.org\/wiki\/Myocarditis \"Myocarditis\") [Chagas disease](https:\/\/en.wikipedia.org\/wiki\/Chagas_disease \"Chagas disease\") [Cardiomyopathy](https:\/\/en.wikipedia.org\/wiki\/Cardiomyopathy \"Cardiomyopathy\") [Dilated](https:\/\/en.wikipedia.org\/wiki\/Dilated_cardiomyopathy \"Dilated cardiomyopathy\") [Alcoholic](https:\/\/en.wikipedia.org\/wiki\/Alcoholic_cardiomyopathy \"Alcoholic cardiomyopathy\") [Hypertrophic](https:\/\/en.wikipedia.org\/wiki\/Hypertrophic_cardiomyopathy \"Hypertrophic cardiomyopathy\") [Tachycardia-induced](https:\/\/en.wikipedia.org\/wiki\/Tachycardia-induced_cardiomyopathy \"Tachycardia-induced cardiomyopathy\") [Restrictive](https:\/\/en.wikipedia.org\/wiki\/Restrictive_cardiomyopathy \"Restrictive cardiomyopathy\") [Loeffler endocarditis](https:\/\/en.wikipedia.org\/wiki\/Loeffler_endocarditis \"Loeffler endocarditis\") [Cardiac amyloidosis](https:\/\/en.wikipedia.org\/wiki\/Amyloidosis \"Amyloidosis\") [Endocardial fibroelastosis](https:\/\/en.wikipedia.org\/wiki\/Endocardial_fibroelastosis \"Endocardial fibroelastosis\") [Viral](https:\/\/en.wikipedia.org\/wiki\/Viral_cardiomyopathy \"Viral cardiomyopathy\") [Arrhythmogenic right ventricular dysplasia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmogenic_right_ventricular_dysplasia \"Arrhythmogenic right ventricular dysplasia\") |\n| [Endocardium](https:\/\/en.wikipedia.org\/wiki\/Endocardium \"Endocardium\") \/  [valves](https:\/\/en.wikipedia.org\/wiki\/Valvular_heart_disease \"Valvular heart disease\") |   |\n|   |   |\n| [Endocarditis](https:\/\/en.wikipedia.org\/wiki\/Endocarditis \"Endocarditis\") | *[infective endocarditis](https:\/\/en.wikipedia.org\/wiki\/Infective_endocarditis \"Infective endocarditis\")* [Subacute bacterial endocarditis](https:\/\/en.wikipedia.org\/wiki\/Subacute_bacterial_endocarditis \"Subacute bacterial endocarditis\") *[non-infective endocarditis](https:\/\/en.wikipedia.org\/wiki\/Endocarditis#Non-infective_endocarditis \"Endocarditis\")* [Libman–Sacks endocarditis](https:\/\/en.wikipedia.org\/wiki\/Libman%E2%80%93Sacks_endocarditis \"Libman–Sacks endocarditis\") [Nonbacterial thrombotic endocarditis](https:\/\/en.wikipedia.org\/wiki\/Nonbacterial_thrombotic_endocarditis \"Nonbacterial thrombotic endocarditis\") |\n| Valves | *[mitral](https:\/\/en.wikipedia.org\/wiki\/Mitral_valve \"Mitral valve\")* [prolapse](https:\/\/en.wikipedia.org\/wiki\/Mitral_valve_prolapse \"Mitral valve prolapse\") [stenosis](https:\/\/en.wikipedia.org\/wiki\/Mitral_valve_stenosis \"Mitral valve stenosis\") [regurgitation](https:\/\/en.wikipedia.org\/wiki\/Mitral_regurgitation \"Mitral regurgitation\") *[aortic](https:\/\/en.wikipedia.org\/wiki\/Aortic_valve \"Aortic valve\")* [stenosis](https:\/\/en.wikipedia.org\/wiki\/Aortic_stenosis \"Aortic stenosis\") [regurgitation](https:\/\/en.wikipedia.org\/wiki\/Aortic_regurgitation \"Aortic regurgitation\") *[tricuspid](https:\/\/en.wikipedia.org\/wiki\/Tricuspid_valve \"Tricuspid valve\")* [stenosis](https:\/\/en.wikipedia.org\/wiki\/Tricuspid_valve_stenosis \"Tricuspid valve stenosis\") [regurgitation](https:\/\/en.wikipedia.org\/wiki\/Tricuspid_regurgitation \"Tricuspid regurgitation\") *[pulmonary](https:\/\/en.wikipedia.org\/wiki\/Pulmonary_valve \"Pulmonary valve\")* [stenosis](https:\/\/en.wikipedia.org\/wiki\/Pulmonary_valve_stenosis \"Pulmonary valve stenosis\") [regurgitation](https:\/\/en.wikipedia.org\/wiki\/Pulmonary_regurgitation \"Pulmonary regurgitation\") |\n| [Conduction](https:\/\/en.wikipedia.org\/wiki\/Cardiac_conduction_system \"Cardiac conduction system\") \/  [arrhythmia]() |   |\n|   |   |\n| [Bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\") | [Sinus bradycardia](https:\/\/en.wikipedia.org\/wiki\/Sinus_bradycardia \"Sinus bradycardia\") [Sick sinus syndrome](https:\/\/en.wikipedia.org\/wiki\/Sick_sinus_syndrome \"Sick sinus syndrome\") [Heart block](https:\/\/en.wikipedia.org\/wiki\/Heart_block \"Heart block\"): [Sinoatrial](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_block \"Sinoatrial block\") [AV](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_block \"Atrioventricular block\") [1°](https:\/\/en.wikipedia.org\/wiki\/First-degree_atrioventricular_block \"First-degree atrioventricular block\") [2°](https:\/\/en.wikipedia.org\/wiki\/Second-degree_atrioventricular_block \"Second-degree atrioventricular block\") [3°](https:\/\/en.wikipedia.org\/wiki\/Third-degree_atrioventricular_block \"Third-degree atrioventricular block\") [Intraventricular](https:\/\/en.wikipedia.org\/wiki\/Intraventricular_block \"Intraventricular block\") [Bundle branch block](https:\/\/en.wikipedia.org\/wiki\/Bundle_branch_block \"Bundle branch block\") [Right](https:\/\/en.wikipedia.org\/wiki\/Right_bundle_branch_block \"Right bundle branch block\") [Left](https:\/\/en.wikipedia.org\/wiki\/Left_bundle_branch_block \"Left bundle branch block\") [Left anterior fascicle](https:\/\/en.wikipedia.org\/wiki\/Left_anterior_fascicular_block \"Left anterior fascicular block\") [Left posterior fascicle](https:\/\/en.wikipedia.org\/wiki\/Left_posterior_fascicular_block \"Left posterior fascicular block\") [Bifascicular](https:\/\/en.wikipedia.org\/wiki\/Bifascicular_block \"Bifascicular block\") [Trifascicular](https:\/\/en.wikipedia.org\/wiki\/Trifascicular_block \"Trifascicular block\") [Adams–Stokes syndrome](https:\/\/en.wikipedia.org\/wiki\/Adams%E2%80%93Stokes_syndrome \"Adams–Stokes syndrome\") |\n| [Tachycardia](https:\/\/en.wikipedia.org\/wiki\/Tachycardia \"Tachycardia\")  ([paroxysmal](https:\/\/en.wikipedia.org\/wiki\/Paroxysmal_tachycardia \"Paroxysmal tachycardia\") and [sinus](https:\/\/en.wikipedia.org\/wiki\/Sinus_tachycardia \"Sinus tachycardia\")) |   |\n|   |   |\n| [Supraventricular](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\") | [Atrial](https:\/\/en.wikipedia.org\/wiki\/Atrial_tachycardia \"Atrial tachycardia\") [Multifocal](https:\/\/en.wikipedia.org\/wiki\/Multifocal_atrial_tachycardia \"Multifocal atrial tachycardia\") [Junctional](https:\/\/en.wikipedia.org\/wiki\/Junctional_tachycardia \"Junctional tachycardia\") [AV nodal reentrant](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\") [Junctional ectopic](https:\/\/en.wikipedia.org\/wiki\/Junctional_ectopic_tachycardia \"Junctional ectopic tachycardia\") |\n| [Ventricular](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\") | [Accelerated idioventricular rhythm](https:\/\/en.wikipedia.org\/wiki\/Accelerated_idioventricular_rhythm \"Accelerated idioventricular rhythm\") [Catecholaminergic polymorphic](https:\/\/en.wikipedia.org\/wiki\/Catecholaminergic_polymorphic_ventricular_tachycardia \"Catecholaminergic polymorphic ventricular tachycardia\") [Torsades de pointes](https:\/\/en.wikipedia.org\/wiki\/Torsades_de_pointes \"Torsades de pointes\") |\n| Premature contraction | [Atrial](https:\/\/en.wikipedia.org\/wiki\/Premature_atrial_contraction \"Premature atrial contraction\") [Junctional](https:\/\/en.wikipedia.org\/wiki\/Premature_junctional_contraction \"Premature junctional contraction\") [Ventricular](https:\/\/en.wikipedia.org\/wiki\/Premature_ventricular_contraction \"Premature ventricular contraction\") |\n| [Pre-excitation syndrome](https:\/\/en.wikipedia.org\/wiki\/Pre-excitation_syndrome \"Pre-excitation syndrome\") | [Lown–Ganong–Levine](https:\/\/en.wikipedia.org\/wiki\/Lown%E2%80%93Ganong%E2%80%93Levine_syndrome \"Lown–Ganong–Levine syndrome\") [Wolff–Parkinson–White](https:\/\/en.wikipedia.org\/wiki\/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome \"Wolff–Parkinson–White syndrome\") |\n| Flutter \/ [fibrillation](https:\/\/en.wikipedia.org\/wiki\/Fibrillation \"Fibrillation\") | [Atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\") [Ventricular flutter](https:\/\/en.wikipedia.org\/wiki\/Ventricular_flutter \"Ventricular flutter\") [Atrial fibrillation](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\") [Familial](https:\/\/en.wikipedia.org\/wiki\/Familial_atrial_fibrillation \"Familial atrial fibrillation\") [Ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\") |\n| [Pacemaker](https:\/\/en.wikipedia.org\/wiki\/Artificial_cardiac_pacemaker \"Artificial cardiac pacemaker\") | [Ectopic pacemaker](https:\/\/en.wikipedia.org\/wiki\/Ectopic_pacemaker \"Ectopic pacemaker\") \/ [Ectopic beat](https:\/\/en.wikipedia.org\/wiki\/Ectopic_beat \"Ectopic beat\") [Multifocal atrial tachycardia](https:\/\/en.wikipedia.org\/wiki\/Multifocal_atrial_tachycardia \"Multifocal atrial tachycardia\") [Pacemaker syndrome](https:\/\/en.wikipedia.org\/wiki\/Pacemaker_syndrome \"Pacemaker syndrome\") [Parasystole](https:\/\/en.wikipedia.org\/wiki\/Parasystole \"Parasystole\") [Wandering atrial pacemaker](https:\/\/en.wikipedia.org\/wiki\/Wandering_atrial_pacemaker \"Wandering atrial pacemaker\") |\n| [Long QT syndrome](https:\/\/en.wikipedia.org\/wiki\/Long_QT_syndrome \"Long QT syndrome\") | [Andersen–Tawil](https:\/\/en.wikipedia.org\/wiki\/Andersen%E2%80%93Tawil_syndrome \"Andersen–Tawil syndrome\") [Jervell and Lange-Nielsen](https:\/\/en.wikipedia.org\/wiki\/Jervell_and_Lange-Nielsen_syndrome \"Jervell and Lange-Nielsen syndrome\") [Romano–Ward](https:\/\/en.wikipedia.org\/wiki\/Romano%E2%80%93Ward_syndrome \"Romano–Ward syndrome\") |\n| [Cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\") | [Sudden cardiac death](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\") [Asystole](https:\/\/en.wikipedia.org\/wiki\/Asystole \"Asystole\") [Pulseless electrical activity](https:\/\/en.wikipedia.org\/wiki\/Pulseless_electrical_activity \"Pulseless electrical activity\") [Sinoatrial arrest](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_arrest \"Sinoatrial arrest\") |\n| Other \/ ungrouped | *[hexaxial reference system](https:\/\/en.wikipedia.org\/wiki\/Hexaxial_reference_system \"Hexaxial reference system\")* [Right axis deviation](https:\/\/en.wikipedia.org\/wiki\/Right_axis_deviation \"Right axis deviation\") [Left axis deviation](https:\/\/en.wikipedia.org\/wiki\/Left_axis_deviation \"Left axis deviation\") *[QT](https:\/\/en.wikipedia.org\/wiki\/QT_interval \"QT interval\")* [Short QT syndrome](https:\/\/en.wikipedia.org\/wiki\/Short_QT_syndrome \"Short QT syndrome\") *[T](https:\/\/en.wikipedia.org\/wiki\/T_wave \"T wave\")* [T wave alternans](https:\/\/en.wikipedia.org\/wiki\/T_wave_alternans \"T wave alternans\") *[ST](https:\/\/en.wikipedia.org\/wiki\/ST_segment \"ST segment\")* [J wave](https:\/\/en.wikipedia.org\/wiki\/J_wave \"J wave\") [ST elevation](https:\/\/en.wikipedia.org\/wiki\/ST_elevation \"ST elevation\") [ST depression](https:\/\/en.wikipedia.org\/wiki\/ST_depression \"ST depression\") [Strain pattern](https:\/\/en.wikipedia.org\/wiki\/Strain_pattern \"Strain pattern\") |\n| [Cardiomegaly](https:\/\/en.wikipedia.org\/wiki\/Cardiomegaly \"Cardiomegaly\") | [Ventricular hypertrophy](https:\/\/en.wikipedia.org\/wiki\/Ventricular_hypertrophy \"Ventricular hypertrophy\") [Left](https:\/\/en.wikipedia.org\/wiki\/Left_ventricular_hypertrophy \"Left ventricular hypertrophy\") [Right](https:\/\/en.wikipedia.org\/wiki\/Right_ventricular_hypertrophy \"Right ventricular hypertrophy\") [Pulmonary](https:\/\/en.wikipedia.org\/wiki\/Pulmonary_heart_disease \"Pulmonary heart disease\") [Atrial enlargement](https:\/\/en.wikipedia.org\/wiki\/Atrial_enlargement \"Atrial enlargement\") [Left](https:\/\/en.wikipedia.org\/wiki\/Left_atrial_enlargement \"Left atrial enlargement\") [Right](https:\/\/en.wikipedia.org\/wiki\/Right_atrial_enlargement \"Right atrial enlargement\") [Athletic heart syndrome](https:\/\/en.wikipedia.org\/wiki\/Athletic_heart_syndrome \"Athletic heart syndrome\") |\n| Other | [Cardiac fibrosis](https:\/\/en.wikipedia.org\/wiki\/Cardiac_fibrosis \"Cardiac fibrosis\") [Heart failure](https:\/\/en.wikipedia.org\/wiki\/Heart_failure \"Heart failure\") [Diastolic heart failure](https:\/\/en.wikipedia.org\/wiki\/Diastolic_heart_failure \"Diastolic heart failure\") [Cardiac asthma](https:\/\/en.wikipedia.org\/wiki\/Cardiac_asthma \"Cardiac asthma\") [Rheumatic fever](https:\/\/en.wikipedia.org\/wiki\/Rheumatic_fever \"Rheumatic fever\") [Obstructive shock](https:\/\/en.wikipedia.org\/wiki\/Obstructive_shock \"Obstructive shock\") |\n\n| [Authority control databases](https:\/\/en.wikipedia.org\/wiki\/Help:Authority_control \"Help:Authority control\") [![Edit this at Wikidata](https:\/\/upload.wikimedia.org\/wikipedia\/en\/thumb\/8\/8a\/OOjs_UI_icon_edit-ltr-progressive.svg\/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png)](https:\/\/www.wikidata.org\/wiki\/Q189331#identifiers \"Edit this at Wikidata\") |   |\n|---|---|\n| International | [GND](https:\/\/d-nb.info\/gnd\/4024696-6) |\n| National | [United States](https:\/\/id.loc.gov\/authorities\/sh85007430) [France](https:\/\/catalogue.bnf.fr\/ark:\/12148\/cb11957225g) [BnF data](https:\/\/data.bnf.fr\/ark:\/12148\/cb11957225g) [Japan](https:\/\/id.ndl.go.jp\/auth\/ndlna\/00563779) [Czech Republic](https:\/\/aleph.nkp.cz\/F\/?func=find-c&local_base=aut&ccl_term=ica=ph126000&CON_LNG=ENG) [2](https:\/\/aleph.nkp.cz\/F\/?func=find-c&local_base=aut&ccl_term=ica=ph841564&CON_LNG=ENG) [Latvia](https:\/\/kopkatalogs.lv\/F?func=direct&local_base=lnc10&doc_number=000113876&P_CON_LNG=ENG) [Poland](https:\/\/dbn.bn.org.pl\/descriptor-details\/9810553796805606) [Israel](https:\/\/www.nli.org.il\/en\/authorities\/987007294978205171) |\n| Other | [Yale LUX](https:\/\/lux.collections.yale.edu\/view\/concept\/e62169b7-40db-4221-80be-6e0117df1f5c) |\n\n![](https:\/\/en.wikipedia.org\/wiki\/Special:CentralAutoLogin\/start?useformat=desktop&type=1x1&usesul3=1)\n\nRetrieved from \"<https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&oldid=1341739168>\"\n\n[Categories](https:\/\/en.wikipedia.org\/wiki\/Help:Category \"Help:Category\"):\n\n- [Cardiac arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Category:Cardiac_arrhythmia \"Category:Cardiac arrhythmia\")\n- [Medical emergencies](https:\/\/en.wikipedia.org\/wiki\/Category:Medical_emergencies \"Category:Medical emergencies\")\n\nHidden categories:\n\n- [Wikipedia articles needing page number citations from August 2021](https:\/\/en.wikipedia.org\/wiki\/Category:Wikipedia_articles_needing_page_number_citations_from_August_2021 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view](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&mobileaction=toggle_view_mobile)\n\n- [![Wikimedia Foundation](https:\/\/en.wikipedia.org\/static\/images\/footer\/wikimedia.svg)](https:\/\/www.wikimedia.org\/)\n- [![Powered by MediaWiki](https:\/\/en.wikipedia.org\/w\/resources\/assets\/mediawiki_compact.svg)](https:\/\/www.mediawiki.org\/)\n\nSearch\n\nToggle the table of contents\n\nArrhythmia\n\n70 languages\n\n[Add topic](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia)","attrs_readable_markdown":"| Arrhythmia |   |\n|---|---|\n| Other names | Cardiac arrhythmia, heart arrhythmia, dysrhythmia, irregular heartbeat |\n| [![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/f\/f1\/Ventricular_fibrillation.png\/330px-Ventricular_fibrillation.png)](https:\/\/en.wikipedia.org\/wiki\/File:Ventricular_fibrillation.png) |   |\n| [Ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\") (VF) showing disorganized electrical activity producing a spiked tracing on an [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") (ECG) |   |\n| [Specialty](https:\/\/en.wikipedia.org\/wiki\/Medical_specialty \"Medical specialty\") | [Cardiology](https:\/\/en.wikipedia.org\/wiki\/Cardiology \"Cardiology\") |\n| [Symptoms](https:\/\/en.wikipedia.org\/wiki\/Signs_and_symptoms \"Signs and symptoms\") | [Palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitations \"Palpitations\"), [dizziness](https:\/\/en.wikipedia.org\/wiki\/Dizziness \"Dizziness\") or [lightheadedness](https:\/\/en.wikipedia.org\/wiki\/Presyncope \"Presyncope\"), [passing out](https:\/\/en.wikipedia.org\/wiki\/Syncope_\\(medicine\\) \"Syncope (medicine)\"), [shortness of breath](https:\/\/en.wikipedia.org\/wiki\/Shortness_of_breath \"Shortness of breath\"), [chest pain](https:\/\/en.wikipedia.org\/wiki\/Chest_pain \"Chest pain\"),[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) [decreased level of consciousness](https:\/\/en.wikipedia.org\/wiki\/Decreased_level_of_consciousness \"Decreased level of consciousness\") |\n| [Complications](https:\/\/en.wikipedia.org\/wiki\/Complication_\\(medicine\\) \"Complication (medicine)\") | [Stroke](https:\/\/en.wikipedia.org\/wiki\/Stroke \"Stroke\"), [heart failure](https:\/\/en.wikipedia.org\/wiki\/Heart_failure \"Heart failure\")[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2)[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3), [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\") |\n| Usual onset | Older age[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) |\n| Types | [Extra beats](https:\/\/en.wikipedia.org\/wiki\/Premature_heart_beat \"Premature heart beat\"), [supraventricular tachycardias](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\"), [ventricular arrhythmias](https:\/\/en.wikipedia.org\/wiki\/Ventricular_arrhythmia \"Ventricular arrhythmia\"), [bradyarrhythmias](https:\/\/en.wikipedia.org\/wiki\/Bradyarrhythmia \"Bradyarrhythmia\")[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) |\n| [Causes](https:\/\/en.wikipedia.org\/wiki\/Cause_\\(medicine\\) \"Cause (medicine)\") | Problems with the [electrical conduction system of the heart](https:\/\/en.wikipedia.org\/wiki\/Electrical_conduction_system_of_the_heart \"Electrical conduction system of the heart\")[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) |\n| [Diagnostic method](https:\/\/en.wikipedia.org\/wiki\/Medical_diagnosis \"Medical diagnosis\") | [Electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\"), [Holter monitor](https:\/\/en.wikipedia.org\/wiki\/Holter_monitor \"Holter monitor\")[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Diag-5) |\n| Treatment | Medications, medical procedures ([pacemaker](https:\/\/en.wikipedia.org\/wiki\/Pacemaker \"Pacemaker\")), surgery[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) |\n| Frequency | Millions[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) |\n\n![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/8\/87\/Gnome-mime-sound-openclipart.svg\/60px-Gnome-mime-sound-openclipart.svg.png)\n\nHeart sounds of a girl experiencing arrhythmia after exercising.\n\n**Arrhythmias**, also known as **cardiac arrhythmias**, are irregularities in the [heartbeat](https:\/\/en.wikipedia.org\/wiki\/Cardiac_cycle \"Cardiac cycle\"), including when it is too fast or too slow.[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) Essentially, this is anything but [normal sinus rhythm](https:\/\/en.wikipedia.org\/wiki\/Normal_sinus_rhythm \"Normal sinus rhythm\"). A resting [heart rate](https:\/\/en.wikipedia.org\/wiki\/Heart_rate \"Heart rate\") that is too fast – above 100 beats per minute in adults – is called [tachycardia](https:\/\/en.wikipedia.org\/wiki\/Tachycardia \"Tachycardia\"), and a resting heart rate that is too slow – below 60 beats per minute – is called [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\").[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) Some types of arrhythmias have no [symptoms](https:\/\/en.wikipedia.org\/wiki\/Symptoms \"Symptoms\").[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) Symptoms, when present, may include [palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitations \"Palpitations\") or feeling a pause between heartbeats.[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) In more serious cases, there may be [lightheadedness](https:\/\/en.wikipedia.org\/wiki\/Presyncope \"Presyncope\"), [passing out](https:\/\/en.wikipedia.org\/wiki\/Syncope_\\(medicine\\) \"Syncope (medicine)\"), [shortness of breath](https:\/\/en.wikipedia.org\/wiki\/Shortness_of_breath \"Shortness of breath\"), [chest pain](https:\/\/en.wikipedia.org\/wiki\/Chest_pain \"Chest pain\"), or [decreased level of consciousness](https:\/\/en.wikipedia.org\/wiki\/Decreased_level_of_consciousness \"Decreased level of consciousness\").[\\[1\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Sym-1) While most cases of arrhythmia are not serious, some predispose a person to complications such as [stroke](https:\/\/en.wikipedia.org\/wiki\/Stroke \"Stroke\") or [heart failure](https:\/\/en.wikipedia.org\/wiki\/Heart_failure \"Heart failure\").[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2)[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Others may result in [sudden death](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3)\n\nArrhythmias are often categorized into four groups: [extra beats](https:\/\/en.wikipedia.org\/wiki\/Premature_heart_beat \"Premature heart beat\"), [supraventricular tachycardias](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\"), [ventricular arrhythmias](https:\/\/en.wikipedia.org\/wiki\/Ventricular_arrhythmia \"Ventricular arrhythmia\") and [bradyarrhythmias](https:\/\/en.wikipedia.org\/wiki\/Bradyarrhythmia \"Bradyarrhythmia\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Extra beats include [premature atrial contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_atrial_contraction \"Premature atrial contraction\"), [premature ventricular contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_ventricular_contraction \"Premature ventricular contraction\") and [premature junctional contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_junctional_contractions \"Premature junctional contractions\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Supraventricular tachycardias include [atrial fibrillation](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\"), [atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\") and [paroxysmal supraventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Paroxysmal_supraventricular_tachycardia \"Paroxysmal supraventricular tachycardia\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3) Ventricular arrhythmias include [ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\") and [ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\").[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3)[\\[7\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Martin2012-7) Bradyarrhythmias are due to [sinus node dysfunction](https:\/\/en.wikipedia.org\/wiki\/Sinus_node_dysfunction \"Sinus node dysfunction\") or [atrioventricular conduction disturbances](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_block \"Atrioventricular block\").[\\[8\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-8) Arrhythmias are due to problems with the [electrical conduction system of the heart](https:\/\/en.wikipedia.org\/wiki\/Electrical_conduction_system_of_the_heart \"Electrical conduction system of the heart\").[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) A number of tests can help with diagnosis, including an [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") (ECG) and [Holter monitor](https:\/\/en.wikipedia.org\/wiki\/Holter_monitor \"Holter monitor\").[\\[5\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Diag-5)\n\nMany arrhythmias can be effectively treated.[\\[2\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Def-2) Treatments may include medications, medical procedures such as inserting a [pacemaker](https:\/\/en.wikipedia.org\/wiki\/Pacemaker \"Pacemaker\"), and surgery.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Medications for a fast heart rate may include [beta blockers](https:\/\/en.wikipedia.org\/wiki\/Beta_blockers \"Beta blockers\"), or [antiarrhythmic agents](https:\/\/en.wikipedia.org\/wiki\/Antiarrhythmic_agent \"Antiarrhythmic agent\") such as [procainamide](https:\/\/en.wikipedia.org\/wiki\/Procainamide \"Procainamide\"), which attempt to restore a normal heart rhythm.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) This latter group may have more significant side effects, especially if taken for a long period of time.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Pacemakers are often used for slow heart rates.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Those with an irregular heartbeat are often treated with [blood thinners](https:\/\/en.wikipedia.org\/wiki\/Blood_thinner \"Blood thinner\") to reduce the risk of complications.[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6) Those who have severe symptoms from an arrhythmia or are medically unstable may receive urgent treatment with a [controlled electric shock](https:\/\/en.wikipedia.org\/wiki\/Electric_shock#Medical_uses \"Electric shock\") in the form of [cardioversion](https:\/\/en.wikipedia.org\/wiki\/Cardioversion \"Cardioversion\") or [defibrillation](https:\/\/en.wikipedia.org\/wiki\/Defibrillation \"Defibrillation\").[\\[6\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Tx-6)\n\nArrhythmia affects millions of people.[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population.[\\[9\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Zoni2014-9) Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990.[\\[10\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-GDB2013-10) However, in most recent cases concerning the SARS-CoV‑2 pandemic, cardiac arrhythmias are commonly developed and associated with high morbidity and mortality among patients hospitalized with the COVID-19 infection, due to the infection's ability to cause myocardial injury.[\\[11\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-11) [Sudden cardiac death](https:\/\/en.wikipedia.org\/wiki\/Sudden_cardiac_death \"Sudden cardiac death\") is the cause of about half of deaths due to [cardiovascular disease](https:\/\/en.wikipedia.org\/wiki\/Cardiovascular_disease \"Cardiovascular disease\") and about 15% of all deaths globally.[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Meh2007-12) About 80% of sudden cardiac death is the result of ventricular arrhythmias.[\\[12\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Meh2007-12) Arrhythmias may occur at any age but are more common among older people.[\\[4\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Risk-4) Arrhythmias may also occur in children; however, the normal range for the heart rate varies with age.[\\[3\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-NIH2011Type-3)\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/7\/77\/De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png\/500px-De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png)](https:\/\/en.wikipedia.org\/wiki\/File:De-Atrial_ventricular_\\(CardioNetworks_ECGpedia\\).png)\n\nBroad classification of arrhythmias according to region of heart required to sustain the rhythm\n\nArrhythmia may be classified by rate ([tachycardia](https:\/\/en.wikipedia.org\/wiki\/Tachycardia \"Tachycardia\"), [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\")), mechanism (automaticity, re-entry, triggered) or duration (isolated [premature beats](https:\/\/en.wikipedia.org\/wiki\/Premature_heart_beat \"Premature heart beat\"); couplets; runs, that is 3 or more beats; non-sustained = less than 30 seconds or sustained = over 30 seconds).\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nArrhythmias are also classified by site of origin:\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n- [Sinus bradycardia](https:\/\/en.wikipedia.org\/wiki\/Sinus_bradycardia \"Sinus bradycardia\")\n- [Sinus arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Sinus_arrhythmia \"Sinus arrhythmia\")\n- [Sinus tachycardia](https:\/\/en.wikipedia.org\/wiki\/Sinus_tachycardia \"Sinus tachycardia\")\n- [Premature atrial contractions (PACs)](https:\/\/en.wikipedia.org\/wiki\/Premature_atrial_contraction \"Premature atrial contraction\")\n- [Wandering atrial pacemaker](https:\/\/en.wikipedia.org\/wiki\/Wandering_pacemaker \"Wandering pacemaker\")\n- [Atrial tachycardia](https:\/\/en.wikipedia.org\/wiki\/Atrial_tachycardia \"Atrial tachycardia\")\n- [Multifocal atrial tachycardia](https:\/\/en.wikipedia.org\/wiki\/Multifocal_atrial_tachycardia \"Multifocal atrial tachycardia\")\n- [Supraventricular tachycardia (SVT)](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\")\n- [Atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\")\n- [Atrial fibrillation (Afib)](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\")\n- [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\")\n\n### Junctional arrhythmia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=3 \"Edit section: Junctional arrhythmia\")\\]\n\n- [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\")\n- [Junctional rhythm](https:\/\/en.wikipedia.org\/wiki\/Junctional_rhythm \"Junctional rhythm\")\n- [Junctional tachycardia](https:\/\/en.wikipedia.org\/wiki\/Junctional_tachycardia \"Junctional tachycardia\")\n- [Premature junctional contraction](https:\/\/en.wikipedia.org\/wiki\/Premature_junctional_contraction \"Premature junctional contraction\")\n\n### Ventricular arrhythmia\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=4 \"Edit section: Ventricular arrhythmia\")\\]\n\n- [Premature ventricular contractions](https:\/\/en.wikipedia.org\/wiki\/Premature_ventricular_contraction \"Premature ventricular contraction\") (PVCs), sometimes called ventricular extra beats (VEBs)\n  - Premature ventricular beats occurring after every normal beat are termed [ventricular bigeminy](https:\/\/en.wikipedia.org\/wiki\/Ventricular_bigeminy \"Ventricular bigeminy\")\n  - PVCs that occur at intervals of 2 normal beats to 1 PVC, or 1 normal beat to 2 PVCs, are termed \"PVCs in trigeminy\"[\\[13\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Farzam-13)\n  - Groups of three premature ventricular beats are called triplets and are considered a brief run of [non-sustained ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Non-sustained_ventricular_tachycardia \"Non-sustained ventricular tachycardia\") (NSVT); if the grouping lasts for more than 30 seconds, it is considered sustained [ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\") (VT).[\\[14\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-wagnerNSVT-14)\n- [Accelerated idioventricular rhythm](https:\/\/en.wikipedia.org\/wiki\/Accelerated_idioventricular_rhythm \"Accelerated idioventricular rhythm\")\n- [Monomorphic ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\")\n- [Polymorphic ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Polymorphic_ventricular_tachycardia \"Polymorphic ventricular tachycardia\")\n- [Ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\")\n- [Torsades de pointes](https:\/\/en.wikipedia.org\/wiki\/Torsades_de_pointes \"Torsades de pointes\")\n- [Arrhythmogenic right ventricular dysplasia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmogenic_right_ventricular_dysplasia \"Arrhythmogenic right ventricular dysplasia\")\n- [Re-entry ventricular arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Re-entry_ventricular_arrhythmia \"Re-entry ventricular arrhythmia\")\n\n[Heart blocks](https:\/\/en.wikipedia.org\/wiki\/Heart_block \"Heart block\") are also known as [AV](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\") blocks, because the vast majority of them arise from pathology at the [atrioventricular node](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\"). They are the most common causes of bradycardia:\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n- [First-degree heart block](https:\/\/en.wikipedia.org\/wiki\/First-degree_heart_block \"First-degree heart block\"), which manifests as PR prolongation\n- [Second-degree heart block](https:\/\/en.wikipedia.org\/wiki\/Second-degree_heart_block \"Second-degree heart block\")\n  - [Type 1 Second degree heart block](https:\/\/en.wikipedia.org\/wiki\/Type_1_Second_degree_heart_block \"Type 1 Second degree heart block\"), also known as [Mobitz I](https:\/\/en.wikipedia.org\/wiki\/Mobitz_I \"Mobitz I\") or [Wenckebach](https:\/\/en.wikipedia.org\/wiki\/Wenckebach \"Wenckebach\")\n  - [Type 2 Second degree heart block](https:\/\/en.wikipedia.org\/wiki\/Type_2_Second_degree_heart_block \"Type 2 Second degree heart block\"), also known as [Mobitz II](https:\/\/en.wikipedia.org\/wiki\/Mobitz_II \"Mobitz II\")\n- [Third-degree heart block](https:\/\/en.wikipedia.org\/wiki\/Third-degree_heart_block \"Third-degree heart block\"), also known as [complete heart block](https:\/\/en.wikipedia.org\/wiki\/Complete_heart_block \"Complete heart block\")\n\nFirst, second, and third-degree blocks also can occur at the level of the sinoatrial junction. This is referred to as [sinoatrial block](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_block \"Sinoatrial block\") typically manifesting with various degrees and patterns of [sinus bradycardia](https:\/\/en.wikipedia.org\/wiki\/Sinus_bradycardia \"Sinus bradycardia\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\n### Sudden arrhythmic death syndrome\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=6 \"Edit section: Sudden arrhythmic death syndrome\")\\]\n\n[Sudden arrhythmic death syndrome](https:\/\/en.wikipedia.org\/wiki\/Sudden_arrhythmic_death_syndrome \"Sudden arrhythmic death syndrome\") (SADS), is a term used as part of *sudden unexpected death syndrome* to describe sudden [death](https:\/\/en.wikipedia.org\/wiki\/Death \"Death\") because of [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\") occasioned by an arrhythmia in the presence or absence of any structural heart disease on autopsy. The most common cause of sudden death in the US is [coronary artery disease](https:\/\/en.wikipedia.org\/wiki\/Coronary_artery_disease \"Coronary artery disease\") specifically because of poor oxygenation of the heart muscle, that is [myocardial ischemia](https:\/\/en.wikipedia.org\/wiki\/Myocardial_ischemia \"Myocardial ischemia\") or a [heart attack](https:\/\/en.wikipedia.org\/wiki\/Myocardial_infarction \"Myocardial infarction\")[\\[15\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-15) Approximately 180,000 to 250,000 people die suddenly of this cause every year in the US. SADS may occur from other causes. There are many inherited conditions and heart diseases that can affect young people which can subsequently cause sudden death without advance symptoms.[\\[16\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-16)\n\nCauses of SADS in young people include [viral myocarditis](https:\/\/en.wikipedia.org\/wiki\/Viral_myocarditis \"Viral myocarditis\"), [long QT syndrome](https:\/\/en.wikipedia.org\/wiki\/Long_QT_syndrome \"Long QT syndrome\"), [Brugada syndrome](https:\/\/en.wikipedia.org\/wiki\/Brugada_syndrome \"Brugada syndrome\"), [Catecholaminergic polymorphic ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Catecholaminergic_polymorphic_ventricular_tachycardia \"Catecholaminergic polymorphic ventricular tachycardia\"), [hypertrophic cardiomyopathy](https:\/\/en.wikipedia.org\/wiki\/Hypertrophic_cardiomyopathy \"Hypertrophic cardiomyopathy\") and [arrhythmogenic right ventricular dysplasia](https:\/\/en.wikipedia.org\/wiki\/Arrhythmogenic_right_ventricular_dysplasia \"Arrhythmogenic right ventricular dysplasia\").[\\[17\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Chugh-2008-17)[\\[18\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-18)\n\nArrhythmias may also occur in the [fetus](https:\/\/en.wikipedia.org\/wiki\/Fetus \"Fetus\").[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Batra-19) The normal heart rate of the fetus is between 110 and 160 beats per minute. Any rhythm beyond these limits is abnormal and classed as a fetal arrhythmia. These are mainly the result of premature atrial contractions, usually give no symptoms, and have little consequence. However, around one percent of these will be the result of significant structural damage to the heart.[\\[19\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Batra-19)\n\nThe term cardiac arrhythmia covers a very large number of very different conditions.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nThe most common symptom of arrhythmia is an awareness of an abnormal heartbeat, called [palpitations](https:\/\/en.wikipedia.org\/wiki\/Palpitation \"Palpitation\"). These may be infrequent, frequent, or continuous. Some of these arrhythmias are harmless (though [distracting](https:\/\/en.wikipedia.org\/wiki\/Distracting \"Distracting\") for patients) but some of them predispose to adverse outcomes. Arrhythmias also cause [chest pain](https:\/\/en.wikipedia.org\/wiki\/Chest_pain \"Chest pain\") and [shortness of breath](https:\/\/en.wikipedia.org\/wiki\/Shortness_of_breath \"Shortness of breath\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nSome arrhythmias do not cause symptoms and are not associated with increased mortality. However, some asymptomatic arrhythmias *are* associated with adverse events. Examples include a higher risk of blood clotting within the heart and a higher risk of insufficient blood being transported to the heart because of a weak heartbeat. Other increased risks are of [embolization](https:\/\/en.wikipedia.org\/wiki\/Embolization \"Embolization\") and stroke, heart failure, and sudden cardiac death.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIf an arrhythmia results in a heartbeat that is too fast, too slow, or too weak to supply the body's needs, this manifests as lower blood pressure and may cause lightheadedness, dizziness, syncope, loss of consciousness, [coma](https:\/\/en.wikipedia.org\/wiki\/Coma \"Coma\"), [persistent vegetative state](https:\/\/en.wikipedia.org\/wiki\/Persistent_vegetative_state \"Persistent vegetative state\"), or brain death due to insufficient supply of blood and oxygen to the brain.[\\[20\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-20)\n\nSome types of arrhythmia result in [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\"), or sudden death.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nMedical assessment of the abnormality using an [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") is one way to diagnose and assess the risk of any given arrhythmia.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nCardiac arrhythmia are caused by one of two major mechanisms. The first of arrhythmia is a result of enhanced or abnormal [impulse](https:\/\/en.wikipedia.org\/wiki\/Cardiac_action_potential \"Cardiac action potential\") formation originating at the [pacemaker](https:\/\/en.wikipedia.org\/wiki\/Cardiac_pacemaker \"Cardiac pacemaker\") or the [His](https:\/\/en.wikipedia.org\/wiki\/Bundle_of_His \"Bundle of His\")\\-[Purkinje](https:\/\/en.wikipedia.org\/wiki\/Purkinje_fibers \"Purkinje fibers\") network. The second is due to [re-entry](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#Re-entry) conduction disturbances.[\\[21\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Antzelevitch_2011-21)\n\nCardiac arrhythmia is often first detected by simple but nonspecific means: [auscultation](https:\/\/en.wikipedia.org\/wiki\/Auscultation \"Auscultation\") of the heartbeat with a [stethoscope](https:\/\/en.wikipedia.org\/wiki\/Stethoscope \"Stethoscope\"), or feeling for peripheral [pulses](https:\/\/en.wikipedia.org\/wiki\/Pulse \"Pulse\"). These cannot usually diagnose specific arrhythmia but can give a general indication of the heart rate and whether it is regular or irregular. Not all the electrical impulses of the heart produce audible or palpable beats; in many cardiac arrhythmias, the premature or abnormal beats do not produce an effective pumping action and are experienced as \"skipped\" beats.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nThe simplest *specific* diagnostic test for assessment of heart rhythm is the [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiogram \"Electrocardiogram\") (abbreviated ECG or EKG).[\\[22\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-22)[\\[23\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-23) A [Holter monitor](https:\/\/en.wikipedia.org\/wiki\/Holter_monitor \"Holter monitor\") is an EKG recorded over a 24-hour period, to detect arrhythmias that may happen briefly and unpredictably throughout the day.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nA more advanced study of the heart's electrical activity can be performed to assess the source of the [aberrant](https:\/\/en.wikipedia.org\/wiki\/Cardiac_aberration \"Cardiac aberration\") heart beats. This can be accomplished in an [electrophysiology study](https:\/\/en.wikipedia.org\/wiki\/Electrophysiology_study \"Electrophysiology study\"), an [endovascular procedure](https:\/\/en.wikipedia.org\/wiki\/Endovascular_procedure \"Endovascular procedure\") that uses a catheter to \"listen\" to the electrical activity from within the heart, additionally if the source of the arrhythmias is found, often the abnormal cells can be ablated and the arrhythmia can be permanently corrected. *Transesophageal atrial stimulation* (TAS) instead uses an electrode inserted through the [esophagus](https:\/\/en.wikipedia.org\/wiki\/Esophagus \"Esophagus\") to a part where the distance to the posterior wall of the [left atrium](https:\/\/en.wikipedia.org\/wiki\/Left_atrium \"Left atrium\") is only approximately 5–6 mm (remaining constant in people of different age and weight).[\\[24\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-MeigasKaik2008-24) Transesophageal atrial stimulation can differentiate between [atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\"), [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\") and orthodromic [atrioventricular reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_reentrant_tachycardia \"Atrioventricular reentrant tachycardia\").[\\[25\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25) It can also evaluate the risk in people with [Wolff–Parkinson–White syndrome](https:\/\/en.wikipedia.org\/wiki\/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome \"Wolff–Parkinson–White syndrome\"), as well as terminate [supraventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\") caused by [re-entry](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrhythmia#Re-entry \"Cardiac arrhythmia\").[\\[25\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25)\n\n### Differential diagnosis\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=11 \"Edit section: Differential diagnosis\")\\]\n\n#### Normal electrical activity\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=12 \"Edit section: Normal electrical activity\")\\]\n\nEach heartbeat originates as an electrical impulse from a small area of tissue in the right [atrium](https:\/\/en.wikipedia.org\/wiki\/Atrium_\\(heart\\) \"Atrium (heart)\") of the heart called the [sinus node or sinoatrial node (SA node)](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_node \"Sinoatrial node\"). The impulse initially causes both atria to contract, then activates the [atrioventricular node (AV node)](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\"), which is normally the only electrical connection between the atria and the [ventricles](https:\/\/en.wikipedia.org\/wiki\/Ventricle_\\(heart\\) \"Ventricle (heart)\") (main pumping chambers). The impulse then spreads through both ventricles via the [bundle of His](https:\/\/en.wikipedia.org\/wiki\/Bundle_of_His \"Bundle of His\") and the [Purkinje fibers](https:\/\/en.wikipedia.org\/wiki\/Purkinje_fibers \"Purkinje fibers\") causing a synchronized contraction of the heart muscle and, thus, the pulse.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIn adults, the normal resting heart rate ranges from 60 to 90 beats per minute. The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered normal.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nThe term [sinus arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Respiratory_sinus_arrhythmia \"Respiratory sinus arrhythmia\")[\\[26\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-26) refers to a normal phenomenon of alternating mild acceleration and slowing of the heart rate that occurs with breathing in and out respectively. It is usually quite pronounced in children and steadily decreases with age. This can also be present during [meditation](https:\/\/en.wikipedia.org\/wiki\/Meditation \"Meditation\") breathing exercises that involve deep inhaling and breath holding patterns.[\\[27\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-27)\n\n[![](https:\/\/upload.wikimedia.org\/wikipedia\/commons\/thumb\/1\/1f\/Sinus_pause.PNG\/250px-Sinus_pause.PNG)](https:\/\/en.wikipedia.org\/wiki\/File:Sinus_pause.PNG)\n\nNormal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm.\n\nA slow rhythm (less than 60 beats\/min) is labelled [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\"). This may be caused by a slowed signal from the sinus node (sinus bradycardia), by a pause in the normal activity of the sinus node (sinus arrest), or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block). Heart block comes in varying degrees and severity. It may be caused by reversible poisoning of the AV node (with drugs that impair conduction) or by irreversible damage to the node. Bradycardias may also be present in the normally functioning heart of endurance athletes or other well-conditioned persons. Bradycardia may also occur in [some types of seizures](https:\/\/en.wikipedia.org\/wiki\/Ictal_bradycardia \"Ictal bradycardia\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIn adults and children over 15, resting heart rate faster than 100 beats per minute is labeled [tachycardia](https:\/\/en.wikipedia.org\/wiki\/Tachycardia \"Tachycardia\"). Tachycardia may result in palpitation; however, tachycardia is not *necessarily* an arrhythmia. Increased heart rate is a normal response to physical exercise or emotional stress. This is mediated by the [sympathetic nervous system](https:\/\/en.wikipedia.org\/wiki\/Sympathetic_nervous_system \"Sympathetic nervous system\") on the [sinus node](https:\/\/en.wikipedia.org\/wiki\/Sinus_node \"Sinus node\") and called sinus tachycardia. Other conditions that increase sympathetic nervous system activity in the heart include ingested or injected substances, such as [caffeine](https:\/\/en.wikipedia.org\/wiki\/Caffeine \"Caffeine\") or [amphetamines](https:\/\/en.wikipedia.org\/wiki\/Amphetamines \"Amphetamines\"), and an overactive thyroid gland ([hyperthyroidism](https:\/\/en.wikipedia.org\/wiki\/Hyperthyroidism \"Hyperthyroidism\")) or [anemia](https:\/\/en.wikipedia.org\/wiki\/Anemia \"Anemia\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nTachycardia that is not sinus tachycardia usually results from the addition of abnormal impulses to the normal [cardiac cycle](https:\/\/en.wikipedia.org\/wiki\/Cardiac_cycle \"Cardiac cycle\"). Abnormal impulses can begin by one of three mechanisms: automaticity, re-entry, or triggered activity. A specialized form of re-entry which is both common and problematic is termed fibrillation.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nAlthough the term \"tachycardia\" has been known for over 160 years, bases for the classification of arrhythmias are still being discussed.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nCongenital heart defects are structural or electrical pathway problems in the heart that are present at birth. Anyone can be affected by this because overall health does not play a role in the problem. Problems with the electrical pathway of the heart can cause very fast or even deadly arrhythmias. [Wolff–Parkinson–White syndrome](https:\/\/en.wikipedia.org\/wiki\/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome \"Wolff–Parkinson–White syndrome\") is due to an extra pathway in the heart that is made up of electrical muscle tissue. This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly. Right [ventricular outflow tract](https:\/\/en.wikipedia.org\/wiki\/Ventricular_outflow_tract \"Ventricular outflow tract\") tachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals. This defect is due to an electrical node in the right ventricle just before the pulmonary artery. When the node is stimulated, the patient will go into ventricular tachycardia, which does not allow the heart to fill with blood before beating again. [Long QT syndrome](https:\/\/en.wikipedia.org\/wiki\/Long_QT_syndrome \"Long QT syndrome\") is another complex problem in the heart and has been labeled as an independent factor in mortality. There are multiple methods of treatment for these including cardiac ablations, medication treatment, or lifestyle changes to have less stress and exercise.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nAutomaticity refers to a [cardiac muscle](https:\/\/en.wikipedia.org\/wiki\/Cardiac_muscle \"Cardiac muscle\") cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an [action potential](https:\/\/en.wikipedia.org\/wiki\/Action_potential \"Action potential\"); however, only some of these cells are designed to routinely trigger heartbeats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His, and Purkinje fibers. The [sinoatrial node](https:\/\/en.wikipedia.org\/wiki\/Sinoatrial_node \"Sinoatrial node\") is a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heartbeat.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nAny part of the heart that initiates an impulse without waiting for the sinoatrial node is called an [ectopic](https:\/\/en.wikipedia.org\/wiki\/Cardiac_ectopy \"Cardiac ectopy\") focus and is, by definition, a pathological phenomenon. This may cause a single premature beat now and then, or, if the [ectopic focus](https:\/\/en.wikipedia.org\/wiki\/Ectopic_focus \"Ectopic focus\") fires more often than the sinoatrial node, it can produce a sustained abnormal rhythm. Rhythms produced by an ectopic focus in the atria, or by the [atrioventricular node](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\"), are the least dangerous dysrhythmias; but they can still produce a decrease in the heart's pumping efficiency because the signal reaches the various parts of the heart muscle with different timing than usual and can be responsible for poorly coordinated contraction.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nConditions that increase automaticity include [sympathetic nervous system](https:\/\/en.wikipedia.org\/wiki\/Sympathetic_nervous_system \"Sympathetic nervous system\") stimulation and [hypoxia](https:\/\/en.wikipedia.org\/wiki\/Hypoxia_\\(medical\\) \"Hypoxia (medical)\"). The resulting heart rhythm depends on where the first signal begins: If it is the sinoatrial node, the rhythm remains normal but rapid; if it is an ectopic focus, many types of dysrhythmia may ensue.\n\nRe-entrant arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping.[\\[28\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Wiener-1946-28)[\\[29\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Allessie-1976-29)\n\nEvery cardiac cell can transmit [impulses of excitation](https:\/\/en.wikipedia.org\/wiki\/Autowave \"Autowave\") in every direction but will do so only once within a short time. Normally, the [action potential](https:\/\/en.wikipedia.org\/wiki\/Action_potential \"Action potential\") impulse will spread through the heart quickly enough that each cell will respond only once. However, if there is some essential heterogeneity of [refractory period](https:\/\/en.wikipedia.org\/wiki\/Refractory_period_\\(physiology\\) \"Refractory period (physiology)\") or if conduction is abnormally slow in some areas (for example in heart damage) so the myocardial cells are unable to activate the fast sodium channel, part of the impulse will arrive late and potentially be treated as a new impulse. Depending on the timing, this can produce a sustained abnormal circuit rhythm.\n\nAs a sort of *re-entry*, vortices of excitation in the myocardium ([autowave vortices](https:\/\/en.wikipedia.org\/wiki\/Autowave \"Autowave\")) are considered to be the main mechanism of life-threatening cardiac arrhythmias.[\\[30\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-b-Mandel-1995-30) In particular, the [autowave reverberator](https:\/\/en.wikipedia.org\/wiki\/Autowave_reverberator \"Autowave reverberator\") is common in the thin walls of the atria, sometimes resulting in [atrial flutter](https:\/\/en.wikipedia.org\/wiki\/Atrial_flutter \"Atrial flutter\"). Re-entry is also responsible for most [paroxysmal supraventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Paroxysmal_supraventricular_tachycardia \"Paroxysmal supraventricular tachycardia\"), and dangerous [ventricular tachycardia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_tachycardia \"Ventricular tachycardia\"). These types of re-entry circuits are different from [WPW](https:\/\/en.wikipedia.org\/wiki\/WPW \"WPW\") syndromes, which utilize abnormal conduction pathways.\n\nAlthough [omega-3 fatty acids](https:\/\/en.wikipedia.org\/wiki\/Omega-3_fatty_acid \"Omega-3 fatty acid\") from [fish oil](https:\/\/en.wikipedia.org\/wiki\/Fish_oil \"Fish oil\") can be protective against arrhythmias, they can facilitate re-entrant arrhythmias.[\\[31\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-a-_Coronel-2007-31)\n\nWhen an entire chamber of the heart is involved in multiple micro-re-entry circuits and is, therefore, quivering with chaotic electrical impulses, it is said to be in fibrillation.\n\nFibrillation can affect the atrium ([atrial fibrillation](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\")) or the ventricle ([ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\")): ventricular fibrillation is imminently life-threatening.\n\n- Atrial fibrillation affects the upper chambers of the heart, known as the [atria](https:\/\/en.wikipedia.org\/wiki\/Atrium_\\(heart\\) \"Atrium (heart)\"). Atrial fibrillation may be due to serious underlying medical conditions and should be evaluated by a [physician](https:\/\/en.wikipedia.org\/wiki\/Physician \"Physician\"). It is not typically a medical emergency.\n- Ventricular fibrillation occurs in the [ventricles](https:\/\/en.wikipedia.org\/wiki\/Ventricle_\\(heart\\) \"Ventricle (heart)\") (lower chambers) of the heart; it is always a medical emergency. If left untreated, [ventricular fibrillation](https:\/\/en.wikipedia.org\/wiki\/Ventricular_fibrillation \"Ventricular fibrillation\") (VF, or V-fib) can lead to death within minutes. When a heart goes into V-fib, effective pumping of the blood stops. V-fib is considered a form of [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\"). An affected individual will not survive unless [cardiopulmonary resuscitation](https:\/\/en.wikipedia.org\/wiki\/Cardiopulmonary_resuscitation \"Cardiopulmonary resuscitation\") (CPR) and [defibrillation](https:\/\/en.wikipedia.org\/wiki\/Defibrillation \"Defibrillation\") are provided immediately.\n\nCPR can prolong the survival of the [brain](https:\/\/en.wikipedia.org\/wiki\/Brain \"Brain\") in the lack of a normal pulse, but defibrillation is the only intervention that can restore a healthy heart rhythm. Defibrillation is performed by applying an electric shock to the heart, which resets the cells, permitting a normal beat to re-establish itself.\n\nTriggered beats occur when problems at the level of the ion channels in individual heart cells result in abnormal propagation of electrical activity and can lead to a sustained abnormal rhythm. They are relatively rare and can result from the action of anti-arrhythmic drugs, or after [depolarizations](https:\/\/en.wikipedia.org\/wiki\/Depolarization \"Depolarization\").\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nThe method of cardiac rhythm management depends firstly on whether the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro- or cryo-cautery.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nIn the United States, people admitted to the hospital with cardiac arrhythmia and conduction disorders with and without complications were admitted to the intensive care unit more than half the time in 2011.[\\[32\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-32)\n\nSeveral physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop several arrhythmias that originate above or at the AV node (see main article: [supraventricular tachycardias](https:\/\/en.wikipedia.org\/wiki\/Supraventricular_tachycardia \"Supraventricular tachycardia\")). Parasympathetic nervous supply to the heart is via the [vagus nerve](https:\/\/en.wikipedia.org\/wiki\/Vagus_nerve \"Vagus nerve\"), and these maneuvers are collectively known as [vagal maneuvers](https:\/\/en.wikipedia.org\/wiki\/Vagal_maneuver \"Vagal maneuver\").\n\n### Antiarrhythmic drugs\n\\[[edit](https:\/\/en.wikipedia.org\/w\/index.php?title=Arrhythmia&action=edit&section=22 \"Edit section: Antiarrhythmic drugs\")\\]\n\nThere are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes. Although the goal of drug therapy is to prevent arrhythmia, nearly every antiarrhythmic drug has the potential to act as a [pro-arrhythmic](https:\/\/en.wikipedia.org\/wiki\/Pro-arrhythmic \"Pro-arrhythmic\"), and so must be carefully selected and used under medical supervision.\n\nSeveral groups of drugs slow conduction through the heart, without actually preventing an arrhythmia. These drugs can be used to \"rate control\" a fast rhythm and make it physically tolerable for the patient.\\[*[citation needed](https:\/\/en.wikipedia.org\/wiki\/Wikipedia:Citation_needed \"Wikipedia:Citation needed\")*\\]\n\nSome arrhythmias promote blood clotting within the heart and increase the risk of embolus and stroke. [Anticoagulant](https:\/\/en.wikipedia.org\/wiki\/Anticoagulant \"Anticoagulant\") medications such as [warfarin](https:\/\/en.wikipedia.org\/wiki\/Warfarin \"Warfarin\") and [heparins](https:\/\/en.wikipedia.org\/wiki\/Heparin \"Heparin\"), and anti-platelet drugs such as [aspirin](https:\/\/en.wikipedia.org\/wiki\/Aspirin \"Aspirin\") can reduce the risk of clotting.\n\nArrhythmias may also be treated electrically, by applying a shock across the heart – either externally to the chest wall, or internally to the heart via implanted electrodes.[\\[33\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-33)\n\n[Cardioversion](https:\/\/en.wikipedia.org\/wiki\/Cardioversion \"Cardioversion\") is either achieved pharmacologically or via the application of a shock *synchronized* to the underlying heartbeat. It is used for the treatment of supraventricular tachycardias. In elective cardioversion, the recipient is usually sedated or lightly [anesthetized](https:\/\/en.wikipedia.org\/wiki\/Anesthesia \"Anesthesia\") for the procedure.\n\n[Defibrillation](https:\/\/en.wikipedia.org\/wiki\/Defibrillation \"Defibrillation\") differs in that the shock is not synchronized. It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, more electricity is required for defibrillation than for cardioversion. In most defibrillation, the recipient has lost consciousness so there is no need for sedation.\n\nDefibrillation or cardioversion may be accomplished by an [implantable cardioverter-defibrillator](https:\/\/en.wikipedia.org\/wiki\/Implantable_cardioverter-defibrillator \"Implantable cardioverter-defibrillator\") (ICD).\n\nElectrical treatment of arrhythmias also includes [cardiac pacing](https:\/\/en.wikipedia.org\/wiki\/Cardiac_pacing \"Cardiac pacing\"). Temporary pacing may be necessary for reversible causes of very slow heartbeats, or [bradycardia](https:\/\/en.wikipedia.org\/wiki\/Bradycardia \"Bradycardia\") (for example, from [drug overdose](https:\/\/en.wikipedia.org\/wiki\/Drug_overdose \"Drug overdose\") or [myocardial infarction](https:\/\/en.wikipedia.org\/wiki\/Myocardial_infarction \"Myocardial infarction\")). A permanent [pacemaker](https:\/\/en.wikipedia.org\/wiki\/Artificial_pacemaker \"Artificial pacemaker\") may be placed in situations where the bradycardia is not expected to recover.\n\nSome cardiologists further sub-specialize into electrophysiology. In specialized [catheter laboratories](https:\/\/en.wikipedia.org\/wiki\/Catheter \"Catheter\"), they use fine probes inserted through the blood vessels to map electrical activity from within the heart. This allows abnormal areas of conduction to be located very accurately and subsequently destroyed by heat, cold, electrical, or laser probes in a process called [catheter ablation](https:\/\/en.wikipedia.org\/wiki\/Catheter_ablation \"Catheter ablation\").\n\nThis procedure may be completely curative for some forms of arrhythmia, but for others, the success rate remains disappointing. [AV nodal reentrant tachycardia](https:\/\/en.wikipedia.org\/wiki\/AV_nodal_reentrant_tachycardia \"AV nodal reentrant tachycardia\") is often curable by ablating one of the pathways in the [AV node](https:\/\/en.wikipedia.org\/wiki\/Atrioventricular_node \"Atrioventricular node\") (usually the slow pathway). [Atrial fibrillation](https:\/\/en.wikipedia.org\/wiki\/Atrial_fibrillation \"Atrial fibrillation\") can also be treated, by performing a [pulmonary vein](https:\/\/en.wikipedia.org\/wiki\/Pulmonary_vein \"Pulmonary vein\") isolation, but the results are less reliable.\n\nArrhythmias due to medications have been reported since the 1920s with the use of [quinine](https:\/\/en.wikipedia.org\/wiki\/Quinine \"Quinine\").[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Hei2010-34) In the 1960s and 1970s problems with antihistamines and antipsychotics were discovered.[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Hei2010-34) It was not until the 1980s that the underlying issue, [QTc prolongation](https:\/\/en.wikipedia.org\/wiki\/QT_interval#Abnormal_intervals \"QT interval\") was determined.[\\[34\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-Hei2010-34) [Osborn waves](https:\/\/en.wikipedia.org\/wiki\/J_wave \"J wave\") on [electrocardiogram](https:\/\/en.wikipedia.org\/wiki\/Electrocardiography \"Electrocardiography\") ([ECG](https:\/\/en.wikipedia.org\/wiki\/ECG \"ECG\")) are frequent during [targeted temperature management (TTM)](https:\/\/en.wikipedia.org\/wiki\/Targeted_temperature_management \"Targeted temperature management\") after [cardiac arrest](https:\/\/en.wikipedia.org\/wiki\/Cardiac_arrest \"Cardiac arrest\"), particularly in patients treated with 33 °C.[\\[35\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-:0-35) [Osborn waves](https:\/\/en.wikipedia.org\/wiki\/J_wave \"J wave\") are not associated with increased risk of [ventricular arrhythmia](https:\/\/en.wikipedia.org\/wiki\/Ventricular_arrhythmia \"Ventricular arrhythmia\"), and may be considered a [benign](https:\/\/en.wikipedia.org\/wiki\/Benign_early_repolarization \"Benign early repolarization\") physiological phenomenon, associated with lower [mortality](https:\/\/en.wikipedia.org\/wiki\/Mortality_rate \"Mortality rate\") in univariable analyses.[\\[35\\]](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_note-:0-35)\n\n- [Pre-excitation syndrome](https:\/\/en.wikipedia.org\/wiki\/Pre-excitation_syndrome \"Pre-excitation syndrome\")\n- [Holiday heart syndrome](https:\/\/en.wikipedia.org\/wiki\/Holiday_heart_syndrome \"Holiday heart syndrome\")\n\n1. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Sym_1-3)\n   [\"What Are the Signs and Symptoms of an Arrhythmia?\"](https:\/\/www.nhlbi.nih.gov\/health\/arrhythmias\/symptoms). National Heart, Lung, and Blood Institute. July 1, 2011. [Archived](https:\/\/web.archive.org\/web\/20150219081446\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/signs) from the original on 19 February 2015. Retrieved 7 March 2015.\n2. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Def_2-6)\n   [\"What Is Arrhythmia?\"](https:\/\/web.archive.org\/web\/20150302074103\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/). [National Heart, Lung, and Blood Institute](https:\/\/en.wikipedia.org\/wiki\/National_Heart,_Lung,_and_Blood_Institute \"National Heart, Lung, and Blood Institute\"). July 1, 2011. Archived from [the original](http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr) on 2 March 2015. Retrieved 7 March 2015.\n3. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-6) [***h***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-7) [***i***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Type_3-8)\n   [\"Types of Arrhythmia\"](https:\/\/web.archive.org\/web\/20150607165144\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/types). National Heart, Lung, and Blood Institute. July 1, 2011. 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Retrieved 7 March 2015.\n6. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-1) [***c***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-2) [***d***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-3) [***e***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-4) [***f***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-5) [***g***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-NIH2011Tx_6-6)\n   [\"How Are Arrhythmias Treated?\"](https:\/\/web.archive.org\/web\/20150217135319\/http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/treatment). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http:\/\/www.nhlbi.nih.gov\/health\/health-topics\/topics\/arr\/treatment) on 17 February 2015. 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The role of nonuniform recovery of excitability in the occurrence of unidirectional block, as studied with multiple microelectrodes\"](https:\/\/doi.org\/10.1161%2F01.RES.39.2.168). *Circulation Research*. **39** (2): 168–177\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1161\/01.RES.39.2.168](https:\/\/doi.org\/10.1161%2F01.RES.39.2.168). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [939001](https:\/\/pubmed.ncbi.nlm.nih.gov\/939001).\n30. **[^](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-b-Mandel-1995_30-0)**\n    Mandel WJ, ed. (1995). *Cardiac Arrhythmias: Their Mechanisms, Diagnosis, and Management* (3 ed.). Lippincott Williams & Wilkins. 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[PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [20921449](https:\/\/pubmed.ncbi.nlm.nih.gov\/20921449).\n35. ^ [***a***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-:0_35-0) [***b***](https:\/\/en.wikipedia.org\/wiki\/Arrhythmia#cite_ref-:0_35-1)\n    Hadziselimovic E, Thomsen JH, Kjaergaard J, Køber L, Graff C, Pehrson S, et al. (July 2018). [\"Osborn waves following out-of-hospital cardiac arrest—Effect of level of temperature management and risk of arrhythmia and death\"](https:\/\/doi.org\/10.1016\/j.resuscitation.2018.04.037). *Resuscitation*. **128**: 119–125\\. [doi](https:\/\/en.wikipedia.org\/wiki\/Doi_\\(identifier\\) \"Doi (identifier)\"):[10\\.1016\/j.resuscitation.2018.04.037](https:\/\/doi.org\/10.1016%2Fj.resuscitation.2018.04.037). [ISSN](https:\/\/en.wikipedia.org\/wiki\/ISSN_\\(identifier\\) \"ISSN (identifier)\") [0300-9572](https:\/\/search.worldcat.org\/issn\/0300-9572). [PMID](https:\/\/en.wikipedia.org\/wiki\/PMID_\\(identifier\\) \"PMID (identifier)\") [29723608](https:\/\/pubmed.ncbi.nlm.nih.gov\/29723608). [S2CID](https:\/\/en.wikipedia.org\/wiki\/S2CID_\\(identifier\\) \"S2CID (identifier)\") [19236851](https:\/\/api.semanticscholar.org\/CorpusID:19236851).","meta_canonical":null}

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Boilerpipe Text	Arrhythmia Other names Cardiac arrhythmia, heart arrhythmia, dysrhythmia, irregular heartbeat Ventricular fibrillation (VF) showing disorganized electrical activity producing a spiked tracing on an electrocardiogram (ECG) Specialty Cardiology Symptoms Palpitations , dizziness or lightheadedness , passing out , shortness of breath , chest pain , [ 1 ] decreased level of consciousness Complications Stroke , heart failure [ 2 ] [ 3 ] , cardiac arrest Usual onset Older age [ 4 ] Types Extra beats , supraventricular tachycardias , ventricular arrhythmias , bradyarrhythmias [ 3 ] Causes Problems with the electrical conduction system of the heart [ 2 ] Diagnostic method Electrocardiogram , Holter monitor [ 5 ] Treatment Medications, medical procedures ( pacemaker ), surgery [ 6 ] Frequency Millions [ 4 ] Heart sounds of a girl experiencing arrhythmia after exercising. Arrhythmias , also known as cardiac arrhythmias , are irregularities in the heartbeat , including when it is too fast or too slow. [ 2 ] Essentially, this is anything but normal sinus rhythm . A resting heart rate that is too fast – above 100 beats per minute in adults – is called tachycardia , and a resting heart rate that is too slow – below 60 beats per minute – is called bradycardia . [ 2 ] Some types of arrhythmias have no symptoms . [ 1 ] Symptoms, when present, may include palpitations or feeling a pause between heartbeats. [ 1 ] In more serious cases, there may be lightheadedness , passing out , shortness of breath , chest pain , or decreased level of consciousness . [ 1 ] While most cases of arrhythmia are not serious, some predispose a person to complications such as stroke or heart failure . [ 2 ] [ 3 ] Others may result in sudden death . [ 3 ] Arrhythmias are often categorized into four groups: extra beats , supraventricular tachycardias , ventricular arrhythmias and bradyarrhythmias . [ 3 ] Extra beats include premature atrial contractions , premature ventricular contractions and premature junctional contractions . [ 3 ] Supraventricular tachycardias include atrial fibrillation , atrial flutter and paroxysmal supraventricular tachycardia . [ 3 ] Ventricular arrhythmias include ventricular fibrillation and ventricular tachycardia . [ 3 ] [ 7 ] Bradyarrhythmias are due to sinus node dysfunction or atrioventricular conduction disturbances . [ 8 ] Arrhythmias are due to problems with the electrical conduction system of the heart . [ 2 ] A number of tests can help with diagnosis, including an electrocardiogram (ECG) and Holter monitor . [ 5 ] Many arrhythmias can be effectively treated. [ 2 ] Treatments may include medications, medical procedures such as inserting a pacemaker , and surgery. [ 6 ] Medications for a fast heart rate may include beta blockers , or antiarrhythmic agents such as procainamide , which attempt to restore a normal heart rhythm. [ 6 ] This latter group may have more significant side effects, especially if taken for a long period of time. [ 6 ] Pacemakers are often used for slow heart rates. [ 6 ] Those with an irregular heartbeat are often treated with blood thinners to reduce the risk of complications. [ 6 ] Those who have severe symptoms from an arrhythmia or are medically unstable may receive urgent treatment with a controlled electric shock in the form of cardioversion or defibrillation . [ 6 ] Arrhythmia affects millions of people. [ 4 ] In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population. [ 9 ] Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990. [ 10 ] However, in most recent cases concerning the SARS-CoV‑2 pandemic, cardiac arrhythmias are commonly developed and associated with high morbidity and mortality among patients hospitalized with the COVID-19 infection, due to the infection's ability to cause myocardial injury. [ 11 ] Sudden cardiac death is the cause of about half of deaths due to cardiovascular disease and about 15% of all deaths globally. [ 12 ] About 80% of sudden cardiac death is the result of ventricular arrhythmias. [ 12 ] Arrhythmias may occur at any age but are more common among older people. [ 4 ] Arrhythmias may also occur in children; however, the normal range for the heart rate varies with age. [ 3 ] Broad classification of arrhythmias according to region of heart required to sustain the rhythm Arrhythmia may be classified by rate ( tachycardia , bradycardia ), mechanism (automaticity, re-entry, triggered) or duration (isolated premature beats ; couplets; runs, that is 3 or more beats; non-sustained = less than 30 seconds or sustained = over 30 seconds). [ citation needed ] Arrhythmias are also classified by site of origin: [ citation needed ] Sinus bradycardia Sinus arrhythmia Sinus tachycardia Premature atrial contractions (PACs) Wandering atrial pacemaker Atrial tachycardia Multifocal atrial tachycardia Supraventricular tachycardia (SVT) Atrial flutter Atrial fibrillation (Afib) AV nodal reentrant tachycardia Junctional arrhythmia [ edit ] AV nodal reentrant tachycardia Junctional rhythm Junctional tachycardia Premature junctional contraction Ventricular arrhythmia [ edit ] Premature ventricular contractions (PVCs), sometimes called ventricular extra beats (VEBs) Premature ventricular beats occurring after every normal beat are termed ventricular bigeminy PVCs that occur at intervals of 2 normal beats to 1 PVC, or 1 normal beat to 2 PVCs, are termed "PVCs in trigeminy" [ 13 ] Groups of three premature ventricular beats are called triplets and are considered a brief run of non-sustained ventricular tachycardia (NSVT); if the grouping lasts for more than 30 seconds, it is considered sustained ventricular tachycardia (VT). [ 14 ] Accelerated idioventricular rhythm Monomorphic ventricular tachycardia Polymorphic ventricular tachycardia Ventricular fibrillation Torsades de pointes Arrhythmogenic right ventricular dysplasia Re-entry ventricular arrhythmia Heart blocks are also known as AV blocks, because the vast majority of them arise from pathology at the atrioventricular node . They are the most common causes of bradycardia: [ citation needed ] First-degree heart block , which manifests as PR prolongation Second-degree heart block Type 1 Second degree heart block , also known as Mobitz I or Wenckebach Type 2 Second degree heart block , also known as Mobitz II Third-degree heart block , also known as complete heart block First, second, and third-degree blocks also can occur at the level of the sinoatrial junction. This is referred to as sinoatrial block typically manifesting with various degrees and patterns of sinus bradycardia . [ citation needed ] Sudden arrhythmic death syndrome [ edit ] Sudden arrhythmic death syndrome (SADS), is a term used as part of sudden unexpected death syndrome to describe sudden death because of cardiac arrest occasioned by an arrhythmia in the presence or absence of any structural heart disease on autopsy. The most common cause of sudden death in the US is coronary artery disease specifically because of poor oxygenation of the heart muscle, that is myocardial ischemia or a heart attack [ 15 ] Approximately 180,000 to 250,000 people die suddenly of this cause every year in the US. SADS may occur from other causes. There are many inherited conditions and heart diseases that can affect young people which can subsequently cause sudden death without advance symptoms. [ 16 ] Causes of SADS in young people include viral myocarditis , long QT syndrome , Brugada syndrome , Catecholaminergic polymorphic ventricular tachycardia , hypertrophic cardiomyopathy and arrhythmogenic right ventricular dysplasia . [ 17 ] [ 18 ] Arrhythmias may also occur in the fetus . [ 19 ] The normal heart rate of the fetus is between 110 and 160 beats per minute. Any rhythm beyond these limits is abnormal and classed as a fetal arrhythmia. These are mainly the result of premature atrial contractions, usually give no symptoms, and have little consequence. However, around one percent of these will be the result of significant structural damage to the heart. [ 19 ] The term cardiac arrhythmia covers a very large number of very different conditions. [ citation needed ] The most common symptom of arrhythmia is an awareness of an abnormal heartbeat, called palpitations . These may be infrequent, frequent, or continuous. Some of these arrhythmias are harmless (though distracting for patients) but some of them predispose to adverse outcomes. Arrhythmias also cause chest pain and shortness of breath . [ citation needed ] Some arrhythmias do not cause symptoms and are not associated with increased mortality. However, some asymptomatic arrhythmias are associated with adverse events. Examples include a higher risk of blood clotting within the heart and a higher risk of insufficient blood being transported to the heart because of a weak heartbeat. Other increased risks are of embolization and stroke, heart failure, and sudden cardiac death. [ citation needed ] If an arrhythmia results in a heartbeat that is too fast, too slow, or too weak to supply the body's needs, this manifests as lower blood pressure and may cause lightheadedness, dizziness, syncope, loss of consciousness, coma , persistent vegetative state , or brain death due to insufficient supply of blood and oxygen to the brain. [ 20 ] Some types of arrhythmia result in cardiac arrest , or sudden death. [ citation needed ] Medical assessment of the abnormality using an electrocardiogram is one way to diagnose and assess the risk of any given arrhythmia. [ citation needed ] Cardiac arrhythmia are caused by one of two major mechanisms. The first of arrhythmia is a result of enhanced or abnormal impulse formation originating at the pacemaker or the His - Purkinje network. The second is due to re-entry conduction disturbances. [ 21 ] Cardiac arrhythmia is often first detected by simple but nonspecific means: auscultation of the heartbeat with a stethoscope , or feeling for peripheral pulses . These cannot usually diagnose specific arrhythmia but can give a general indication of the heart rate and whether it is regular or irregular. Not all the electrical impulses of the heart produce audible or palpable beats; in many cardiac arrhythmias, the premature or abnormal beats do not produce an effective pumping action and are experienced as "skipped" beats. [ citation needed ] The simplest specific diagnostic test for assessment of heart rhythm is the electrocardiogram (abbreviated ECG or EKG). [ 22 ] [ 23 ] A Holter monitor is an EKG recorded over a 24-hour period, to detect arrhythmias that may happen briefly and unpredictably throughout the day. [ citation needed ] A more advanced study of the heart's electrical activity can be performed to assess the source of the aberrant heart beats. This can be accomplished in an electrophysiology study , an endovascular procedure that uses a catheter to "listen" to the electrical activity from within the heart, additionally if the source of the arrhythmias is found, often the abnormal cells can be ablated and the arrhythmia can be permanently corrected. Transesophageal atrial stimulation (TAS) instead uses an electrode inserted through the esophagus to a part where the distance to the posterior wall of the left atrium is only approximately 5–6 mm (remaining constant in people of different age and weight). [ 24 ] Transesophageal atrial stimulation can differentiate between atrial flutter , AV nodal reentrant tachycardia and orthodromic atrioventricular reentrant tachycardia . [ 25 ] It can also evaluate the risk in people with Wolff–Parkinson–White syndrome , as well as terminate supraventricular tachycardia caused by re-entry . [ 25 ] Differential diagnosis [ edit ] Normal electrical activity [ edit ] Each heartbeat originates as an electrical impulse from a small area of tissue in the right atrium of the heart called the sinus node or sinoatrial node (SA node) . The impulse initially causes both atria to contract, then activates the atrioventricular node (AV node) , which is normally the only electrical connection between the atria and the ventricles (main pumping chambers). The impulse then spreads through both ventricles via the bundle of His and the Purkinje fibers causing a synchronized contraction of the heart muscle and, thus, the pulse. [ citation needed ] In adults, the normal resting heart rate ranges from 60 to 90 beats per minute. The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered normal. [ citation needed ] The term sinus arrhythmia [ 26 ] refers to a normal phenomenon of alternating mild acceleration and slowing of the heart rate that occurs with breathing in and out respectively. It is usually quite pronounced in children and steadily decreases with age. This can also be present during meditation breathing exercises that involve deep inhaling and breath holding patterns. [ 27 ] Normal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm. A slow rhythm (less than 60 beats/min) is labelled bradycardia . This may be caused by a slowed signal from the sinus node (sinus bradycardia), by a pause in the normal activity of the sinus node (sinus arrest), or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block). Heart block comes in varying degrees and severity. It may be caused by reversible poisoning of the AV node (with drugs that impair conduction) or by irreversible damage to the node. Bradycardias may also be present in the normally functioning heart of endurance athletes or other well-conditioned persons. Bradycardia may also occur in some types of seizures . [ citation needed ] In adults and children over 15, resting heart rate faster than 100 beats per minute is labeled tachycardia . Tachycardia may result in palpitation; however, tachycardia is not necessarily an arrhythmia. Increased heart rate is a normal response to physical exercise or emotional stress. This is mediated by the sympathetic nervous system on the sinus node and called sinus tachycardia. Other conditions that increase sympathetic nervous system activity in the heart include ingested or injected substances, such as caffeine or amphetamines , and an overactive thyroid gland ( hyperthyroidism ) or anemia . [ citation needed ] Tachycardia that is not sinus tachycardia usually results from the addition of abnormal impulses to the normal cardiac cycle . Abnormal impulses can begin by one of three mechanisms: automaticity, re-entry, or triggered activity. A specialized form of re-entry which is both common and problematic is termed fibrillation. [ citation needed ] Although the term "tachycardia" has been known for over 160 years, bases for the classification of arrhythmias are still being discussed. [ citation needed ] Congenital heart defects are structural or electrical pathway problems in the heart that are present at birth. Anyone can be affected by this because overall health does not play a role in the problem. Problems with the electrical pathway of the heart can cause very fast or even deadly arrhythmias. Wolff–Parkinson–White syndrome is due to an extra pathway in the heart that is made up of electrical muscle tissue. This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly. Right ventricular outflow tract tachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals. This defect is due to an electrical node in the right ventricle just before the pulmonary artery. When the node is stimulated, the patient will go into ventricular tachycardia, which does not allow the heart to fill with blood before beating again. Long QT syndrome is another complex problem in the heart and has been labeled as an independent factor in mortality. There are multiple methods of treatment for these including cardiac ablations, medication treatment, or lifestyle changes to have less stress and exercise. [ citation needed ] Automaticity refers to a cardiac muscle cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an action potential ; however, only some of these cells are designed to routinely trigger heartbeats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His, and Purkinje fibers. The sinoatrial node is a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heartbeat. [ citation needed ] Any part of the heart that initiates an impulse without waiting for the sinoatrial node is called an ectopic focus and is, by definition, a pathological phenomenon. This may cause a single premature beat now and then, or, if the ectopic focus fires more often than the sinoatrial node, it can produce a sustained abnormal rhythm. Rhythms produced by an ectopic focus in the atria, or by the atrioventricular node , are the least dangerous dysrhythmias; but they can still produce a decrease in the heart's pumping efficiency because the signal reaches the various parts of the heart muscle with different timing than usual and can be responsible for poorly coordinated contraction. [ citation needed ] Conditions that increase automaticity include sympathetic nervous system stimulation and hypoxia . The resulting heart rhythm depends on where the first signal begins: If it is the sinoatrial node, the rhythm remains normal but rapid; if it is an ectopic focus, many types of dysrhythmia may ensue. Re-entrant arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping. [ 28 ] [ 29 ] Every cardiac cell can transmit impulses of excitation in every direction but will do so only once within a short time. Normally, the action potential impulse will spread through the heart quickly enough that each cell will respond only once. However, if there is some essential heterogeneity of refractory period or if conduction is abnormally slow in some areas (for example in heart damage) so the myocardial cells are unable to activate the fast sodium channel, part of the impulse will arrive late and potentially be treated as a new impulse. Depending on the timing, this can produce a sustained abnormal circuit rhythm. As a sort of re-entry , vortices of excitation in the myocardium ( autowave vortices ) are considered to be the main mechanism of life-threatening cardiac arrhythmias. [ 30 ] In particular, the autowave reverberator is common in the thin walls of the atria, sometimes resulting in atrial flutter . Re-entry is also responsible for most paroxysmal supraventricular tachycardia , and dangerous ventricular tachycardia . These types of re-entry circuits are different from WPW syndromes, which utilize abnormal conduction pathways. Although omega-3 fatty acids from fish oil can be protective against arrhythmias, they can facilitate re-entrant arrhythmias. [ 31 ] When an entire chamber of the heart is involved in multiple micro-re-entry circuits and is, therefore, quivering with chaotic electrical impulses, it is said to be in fibrillation. Fibrillation can affect the atrium ( atrial fibrillation ) or the ventricle ( ventricular fibrillation ): ventricular fibrillation is imminently life-threatening. Atrial fibrillation affects the upper chambers of the heart, known as the atria . Atrial fibrillation may be due to serious underlying medical conditions and should be evaluated by a physician . It is not typically a medical emergency. Ventricular fibrillation occurs in the ventricles (lower chambers) of the heart; it is always a medical emergency. If left untreated, ventricular fibrillation (VF, or V-fib) can lead to death within minutes. When a heart goes into V-fib, effective pumping of the blood stops. V-fib is considered a form of cardiac arrest . An affected individual will not survive unless cardiopulmonary resuscitation (CPR) and defibrillation are provided immediately. CPR can prolong the survival of the brain in the lack of a normal pulse, but defibrillation is the only intervention that can restore a healthy heart rhythm. Defibrillation is performed by applying an electric shock to the heart, which resets the cells, permitting a normal beat to re-establish itself. Triggered beats occur when problems at the level of the ion channels in individual heart cells result in abnormal propagation of electrical activity and can lead to a sustained abnormal rhythm. They are relatively rare and can result from the action of anti-arrhythmic drugs, or after depolarizations . [ citation needed ] The method of cardiac rhythm management depends firstly on whether the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro- or cryo-cautery. [ citation needed ] In the United States, people admitted to the hospital with cardiac arrhythmia and conduction disorders with and without complications were admitted to the intensive care unit more than half the time in 2011. [ 32 ] Several physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop several arrhythmias that originate above or at the AV node (see main article: supraventricular tachycardias ). Parasympathetic nervous supply to the heart is via the vagus nerve , and these maneuvers are collectively known as vagal maneuvers . Antiarrhythmic drugs [ edit ] There are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes. Although the goal of drug therapy is to prevent arrhythmia, nearly every antiarrhythmic drug has the potential to act as a pro-arrhythmic , and so must be carefully selected and used under medical supervision. Several groups of drugs slow conduction through the heart, without actually preventing an arrhythmia. These drugs can be used to "rate control" a fast rhythm and make it physically tolerable for the patient. [ citation needed ] Some arrhythmias promote blood clotting within the heart and increase the risk of embolus and stroke. Anticoagulant medications such as warfarin and heparins , and anti-platelet drugs such as aspirin can reduce the risk of clotting. Arrhythmias may also be treated electrically, by applying a shock across the heart – either externally to the chest wall, or internally to the heart via implanted electrodes. [ 33 ] Cardioversion is either achieved pharmacologically or via the application of a shock synchronized to the underlying heartbeat. It is used for the treatment of supraventricular tachycardias. In elective cardioversion, the recipient is usually sedated or lightly anesthetized for the procedure. Defibrillation differs in that the shock is not synchronized. It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, more electricity is required for defibrillation than for cardioversion. In most defibrillation, the recipient has lost consciousness so there is no need for sedation. Defibrillation or cardioversion may be accomplished by an implantable cardioverter-defibrillator (ICD). Electrical treatment of arrhythmias also includes cardiac pacing . Temporary pacing may be necessary for reversible causes of very slow heartbeats, or bradycardia (for example, from drug overdose or myocardial infarction ). A permanent pacemaker may be placed in situations where the bradycardia is not expected to recover. Some cardiologists further sub-specialize into electrophysiology. In specialized catheter laboratories , they use fine probes inserted through the blood vessels to map electrical activity from within the heart. This allows abnormal areas of conduction to be located very accurately and subsequently destroyed by heat, cold, electrical, or laser probes in a process called catheter ablation . This procedure may be completely curative for some forms of arrhythmia, but for others, the success rate remains disappointing. AV nodal reentrant tachycardia is often curable by ablating one of the pathways in the AV node (usually the slow pathway). Atrial fibrillation can also be treated, by performing a pulmonary vein isolation, but the results are less reliable. Arrhythmias due to medications have been reported since the 1920s with the use of quinine . [ 34 ] In the 1960s and 1970s problems with antihistamines and antipsychotics were discovered. [ 34 ] It was not until the 1980s that the underlying issue, QTc prolongation was determined. [ 34 ] Osborn waves on electrocardiogram ( ECG ) are frequent during targeted temperature management (TTM) after cardiac arrest , particularly in patients treated with 33 °C. [ 35 ] Osborn waves are not associated with increased risk of ventricular arrhythmia , and may be considered a benign physiological phenomenon, associated with lower mortality in univariable analyses. [ 35 ] Pre-excitation syndrome Holiday heart syndrome ^ a b c d "What Are the Signs and Symptoms of an Arrhythmia?" . National Heart, Lung, and Blood Institute. July 1, 2011. Archived from the original on 19 February 2015 . Retrieved 7 March 2015 . ^ a b c d e f g "What Is Arrhythmia?" . National Heart, Lung, and Blood Institute . July 1, 2011. Archived from the original on 2 March 2015 . Retrieved 7 March 2015 . ^ a b c d e f g h i "Types of Arrhythmia" . National Heart, Lung, and Blood Institute. July 1, 2011. Archived from the original on 7 June 2015 . Retrieved 7 March 2015 . ^ a b c d "Who Is at Risk for an Arrhythmia?" . National Heart, Lung, and Blood Institute. July 1, 2011. Archived from the original on 3 March 2015 . Retrieved 7 March 2015 . ^ a b "How Are Arrhythmias Diagnosed?" . National Heart, Lung, and Blood Institute. July 1, 2011. Archived from the original on 18 February 2015 . Retrieved 7 March 2015 . ^ a b c d e f g "How Are Arrhythmias Treated?" . National Heart, Lung, and Blood Institute. July 1, 2011. Archived from the original on 17 February 2015 . Retrieved 7 March 2015 . ^ Martin CA, Matthews GD, Huang CL (April 2012). "Sudden cardiac death and inherited channelopathy: the basic electrophysiology of the myocyte and myocardium in ion channel disease" . Heart . 98 (7): 536– 543. doi : 10.1136/heartjnl-2011-300953 . PMC 3308472 . PMID 22422742 . ^ Vogler J, Breithardt G, Eckardt L (July 2012). "Bradyarrhythmias and conduction blocks". Revista Espanola de Cardiologia . 65 (7): 656– 667. doi : 10.1016/j.rec.2012.01.027 . PMID 22627074 . S2CID 18983179 . ^ Zoni-Berisso M, Lercari F, Carazza T, Domenicucci S (2014). "Epidemiology of atrial fibrillation: European perspective" . Clinical Epidemiology . 6 : 213– 220. doi : 10.2147/CLEP.S47385 . PMC 4064952 . PMID 24966695 . ^ Naghavi M, Wang H, Lozano R, Davis A, Liang X, Zhou M, et al. (GBD 2013 Mortality and Causes of Death Collaborators) (January 2015). "Global, regional, and national age-sex specific all-cause and cause-specific mortality for 240 causes of death, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013" . Lancet . 385 (9963): 117– 171. doi : 10.1016/S0140-6736(14)61682-2 . PMC 4340604 . PMID 25530442 . ^ Kuck KH (June 2020). "Arrhythmias and sudden cardiac death in the COVID-19 pandemic" . Herz . 45 (4): 325– 326. doi : 10.1007/s00059-020-04924-0 . PMC 7181098 . PMID 32333026 . ^ a b Mehra R (2007). "Global public health problem of sudden cardiac death". Journal of Electrocardiology . 40 (6 Suppl): S118– S122. doi : 10.1016/j.jelectrocard.2007.06.023 . PMID 17993308 . ^ Farzam K, Richards JR (2022-12-27). "Premature ventricular contraction" . StatPearls. PMID 30422584 . ^ Wagner GS (2001). Marriott's Practical Electrocardiography (10th ed.). Philadelphia, PA: Williams & Wilkins. ISBN 0683307460 . [ page needed ] ^ Zipes DP, Wellens HJ (November 1998). "Sudden cardiac death" . Circulation . 98 (21): 2334– 2351. doi : 10.1161/01.CIR.98.21.2334 . PMID 9826323 . ^ Deo R, Albert CM (January 2012). "Epidemiology and genetics of sudden cardiac death" . Circulation . 125 (4): 620– 637. doi : 10.1161/circulationaha.111.023838 . PMC 3399522 . PMID 22294707 . ^ Chugh SS, Reinier K, Teodorescu C, Evanado A, Kehr E, Al Samara M, et al. (2008). "Epidemiology of sudden cardiac death: clinical and research implications" . Progress in Cardiovascular Diseases . 51 (3): 213– 228. doi : 10.1016/j.pcad.2008.06.003 . PMC 2621010 . PMID 19026856 . ^ Winkel BG, Holst AG, Theilade J, Kristensen IB, Thomsen JL, Ottesen GL, et al. (April 2011). "Nationwide study of sudden cardiac death in persons aged 1-35 years" . European Heart Journal . 32 (8): 983– 990. doi : 10.1093/eurheartj/ehq428 . PMID 21131293 . ^ a b Batra AS, Balaji S (2019). "Fetal arrhythmias: Diagnosis and management" . Indian Pacing and Electrophysiology Journal . 19 (3): 104– 109. doi : 10.1016/j.ipej.2019.02.007 . PMC 6531664 . PMID 30817991 . ^ "Passing Out (Syncope) Caused by Arrhythmias" . Retrieved 13 April 2020 . ^ Antzelevitch C, Burashnikov A (March 2011). "Overview of Basic Mechanisms of Cardiac Arrhythmia" . Cardiac Electrophysiology Clinics . 3 (1): 23– 45. doi : 10.1016/j.ccep.2010.10.012 . PMC 3164530 . PMID 21892379 . ^ Willcox ME, Compton SJ, Bardy GH (2021-12-01). "Continuous ECG monitoring versus mobile telemetry: A comparison of arrhythmia diagnostics in human- versus algorithmic-dependent systems" . Heart Rhythm O2 . 2 (6, Part A): 543– 559. doi : 10.1016/j.hroo.2021.09.008 . ISSN 2666-5018 . PMC 8703156 . PMID 34988499 . ^ Kiladze MR, Lyakhova UA, Lyakhov PA, Nagornov NN, Vahabi M (2023). "Multimodal Neural Network for Recognition of Cardiac Arrhythmias Based on 12-Load Electrocardiogram Signals" . IEEE Access . 11 : 133744– 133754. Bibcode : 2023IEEEA..11m3744K . doi : 10.1109/ACCESS.2023.3335176 . ISSN 2169-3536 . ^ Anier A, Kaik J, Meigas K (2008). "Device and methods for performing transesophageal stimulation at reduced pacing current threshold". Estonian Journal of Engineering . 57 (2): 154. doi : 10.3176/eng.2008.2.05 . S2CID 42055085 . ^ a b Pehrson SM, Blomström-Lundqvist C, Ljungström E, Blomström P (October 1994). "Clinical value of transesophageal atrial stimulation and recording in patients with arrhythmia-related symptoms or documented supraventricular tachycardia--correlation to clinical history and invasive studies" . Clinical Cardiology . 17 (10): 528– 534. doi : 10.1002/clc.4960171004 . PMID 8001299 . S2CID 7097362 . ^ Yasuma F, Hayano J (February 2004). "Respiratory sinus arrhythmia: why does the heartbeat synchronize with respiratory rhythm?". Chest . 125 (2): 683– 690. doi : 10.1378/chest.125.2.683 . PMID 14769752 . ^ Peressutti C, Martín-González JM, M García-Manso J, Mesa D (November 2010). "Heart rate dynamics in different levels of Zen meditation". International Journal of Cardiology . 145 (1): 142– 146. doi : 10.1016/j.ijcard.2009.06.058 . PMID 19631997 . ^ Wiener N, Rosenblueth A (July 1946). "The mathematical formulation of the problem of conduction of impulses in a network of connected excitable elements, specifically in cardiac muscle". Archivos del Instituto de Cardiologia de Mexico . 16 (3): 205– 265. PMID 20245817 . ^ Allessie MA , Bonke FI, Schopman FJ (August 1976). "Circus movement in rabbit atrial muscle as a mechanism of tachycardia. II. The role of nonuniform recovery of excitability in the occurrence of unidirectional block, as studied with multiple microelectrodes" . Circulation Research . 39 (2): 168– 177. doi : 10.1161/01.RES.39.2.168 . PMID 939001 . ^ Mandel WJ, ed. (1995). Cardiac Arrhythmias: Their Mechanisms, Diagnosis, and Management (3 ed.). Lippincott Williams & Wilkins. ISBN 978-0-397-51185-3 . [ page needed ] ^ Den Ruijter HM, Berecki G, Opthof T, Verkerk AO, Zock PL, Coronel R (January 2007). "Pro- and antiarrhythmic properties of a diet rich in fish oil" . Cardiovascular Research . 73 (2): 316– 325. doi : 10.1016/j.cardiores.2006.06.014 . PMID 16859661 . ^ Barrett ML, Smith MW, Elizhauser A, Honigman LS, Pines JM (December 2014). "Utilization of Intensive Care Services, 2011" . HCUP Statistical Brief (185). Rockville, MD: Agency for Healthcare Research and Quality. PMID 25654157 . Archived from the original on 2015-04-02. ^ "AED Buyer's Guide \| AED Prices & Comparison" . AED Brands . Retrieved 2021-08-13 . ^ a b c Heist EK, Ruskin JN (October 2010). "Drug-induced arrhythmia" . Circulation . 122 (14): 1426– 1435. doi : 10.1161/circulationaha.109.894725 . PMID 20921449 . ^ a b Hadziselimovic E, Thomsen JH, Kjaergaard J, Køber L, Graff C, Pehrson S, et al. (July 2018). "Osborn waves following out-of-hospital cardiac arrest—Effect of level of temperature management and risk of arrhythmia and death" . Resuscitation . 128 : 119– 125. doi : 10.1016/j.resuscitation.2018.04.037 . ISSN 0300-9572 . PMID 29723608 . S2CID 19236851 .
Markdown	[Jump to content](https://en.wikipedia.org/wiki/Arrhythmia#bodyContent) Main menu Main menu move to sidebar hide Navigation - [Main page](https://en.wikipedia.org/wiki/Main_Page "Visit the main page [z]") - [Contents](https://en.wikipedia.org/wiki/Wikipedia:Contents "Guides to browsing Wikipedia") - [Current events](https://en.wikipedia.org/wiki/Portal:Current_events "Articles related to current events") - [Random article](https://en.wikipedia.org/wiki/Special:Random "Visit a randomly selected article [x]") - [About Wikipedia](https://en.wikipedia.org/wiki/Wikipedia:About "Learn about Wikipedia and how it works") - [Contact us](https://en.wikipedia.org/wiki/Wikipedia:Contact_us "How to contact Wikipedia") Contribute - [Help](https://en.wikipedia.org/wiki/Help:Contents "Guidance on how to use and edit Wikipedia") - [Learn to edit](https://en.wikipedia.org/wiki/Help:Introduction "Learn how to edit Wikipedia") - [Community portal](https://en.wikipedia.org/wiki/Wikipedia:Community_portal "The hub for editors") - [Recent changes](https://en.wikipedia.org/wiki/Special:RecentChanges "A list of recent changes to Wikipedia [r]") - [Upload file](https://en.wikipedia.org/wiki/Wikipedia:File_upload_wizard "Add images or other media for use on Wikipedia") - [Special pages](https://en.wikipedia.org/wiki/Special:SpecialPages "A list of all special pages [q]") [![](https://en.wikipedia.org/static/images/icons/enwiki-25.svg) ![Wikipedia](https://en.wikipedia.org/static/images/mobile/copyright/wikipedia-wordmark-en-25.svg) ![The Free Encyclopedia](https://en.wikipedia.org/static/images/mobile/copyright/wikipedia-tagline-en-25.svg)](https://en.wikipedia.org/wiki/Main_Page) [Search](https://en.wikipedia.org/wiki/Special:Search "Search Wikipedia [f]") Appearance - [Donate](https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en) - [Create account](https://en.wikipedia.org/w/index.php?title=Special:CreateAccount&returnto=Arrhythmia "You are encouraged to create an account and log in; however, it is not mandatory") - [Log in](https://en.wikipedia.org/w/index.php?title=Special:UserLogin&returnto=Arrhythmia "You're encouraged to log in; however, it's not mandatory. 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[o]") ## Contents move to sidebar hide - [(Top)](https://en.wikipedia.org/wiki/Arrhythmia) - [1 Classification](https://en.wikipedia.org/wiki/Arrhythmia#Classification) Toggle Classification subsection - [1\.1 Atrial arrhythmia](https://en.wikipedia.org/wiki/Arrhythmia#Atrial_arrhythmia) - [1\.2 Junctional arrhythmia](https://en.wikipedia.org/wiki/Arrhythmia#Junctional_arrhythmia) - [1\.3 Ventricular arrhythmia](https://en.wikipedia.org/wiki/Arrhythmia#Ventricular_arrhythmia) - [1\.4 Heart blocks](https://en.wikipedia.org/wiki/Arrhythmia#Heart_blocks) - [1\.5 Sudden arrhythmic death syndrome](https://en.wikipedia.org/wiki/Arrhythmia#Sudden_arrhythmic_death_syndrome) - [1\.6 Fetal arrhythmia](https://en.wikipedia.org/wiki/Arrhythmia#Fetal_arrhythmia) - [2 Signs and symptoms](https://en.wikipedia.org/wiki/Arrhythmia#Signs_and_symptoms) - [3 Mechanism](https://en.wikipedia.org/wiki/Arrhythmia#Mechanism) - [4 Diagnostic](https://en.wikipedia.org/wiki/Arrhythmia#Diagnostic) Toggle Diagnostic subsection - [4\.1 Differential diagnosis](https://en.wikipedia.org/wiki/Arrhythmia#Differential_diagnosis) - [4\.1.1 Normal electrical activity](https://en.wikipedia.org/wiki/Arrhythmia#Normal_electrical_activity) - [4\.1.2 Bradycardias](https://en.wikipedia.org/wiki/Arrhythmia#Bradycardias) - [4\.1.3 Tachycardias](https://en.wikipedia.org/wiki/Arrhythmia#Tachycardias) - [4\.1.4 Heart defects](https://en.wikipedia.org/wiki/Arrhythmia#Heart_defects) - [4\.1.5 Automaticity](https://en.wikipedia.org/wiki/Arrhythmia#Automaticity) - [4\.1.6 Re-entry](https://en.wikipedia.org/wiki/Arrhythmia#Re-entry) - [4\.1.7 Fibrillation](https://en.wikipedia.org/wiki/Arrhythmia#Fibrillation) - [4\.1.8 Triggered beats](https://en.wikipedia.org/wiki/Arrhythmia#Triggered_beats) - [5 Management](https://en.wikipedia.org/wiki/Arrhythmia#Management) Toggle Management subsection - [5\.1 Physical maneuvers](https://en.wikipedia.org/wiki/Arrhythmia#Physical_maneuvers) - [5\.2 Antiarrhythmic drugs](https://en.wikipedia.org/wiki/Arrhythmia#Antiarrhythmic_drugs) - [5\.3 Other drugs](https://en.wikipedia.org/wiki/Arrhythmia#Other_drugs) - [5\.4 Electricity](https://en.wikipedia.org/wiki/Arrhythmia#Electricity) - [5\.5 Electrical cautery](https://en.wikipedia.org/wiki/Arrhythmia#Electrical_cautery) - [6 Research](https://en.wikipedia.org/wiki/Arrhythmia#Research) - [7 See also](https://en.wikipedia.org/wiki/Arrhythmia#See_also) - [8 References](https://en.wikipedia.org/wiki/Arrhythmia#References) - [9 External links](https://en.wikipedia.org/wiki/Arrhythmia#External_links) Toggle the table of contents # Arrhythmia 70 languages - [العربية](https://ar.wikipedia.org/wiki/%D8%A7%D8%B6%D8%B7%D8%B1%D8%A7%D8%A8_%D8%A7%D9%84%D9%86%D8%B8%D9%85 "اضطراب النظم – Arabic") - [Беларуская (тарашкевіца)](https://be-tarask.wikipedia.org/wiki/%D0%90%D1%80%D1%8B%D1%82%D0%BC%D1%96%D1%8F "Арытмія – Belarusian (Taraškievica orthography)") - [Беларуская](https://be.wikipedia.org/wiki/%D0%90%D1%80%D1%8B%D1%82%D0%BC%D1%96%D1%8F "Арытмія – Belarusian") - [Български](https://bg.wikipedia.org/wiki/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F "Аритмия – Bulgarian") - [བོད་ཡིག](https://bo.wikipedia.org/wiki/%E0%BD%A6%E0%BE%99%E0%BD%B2%E0%BD%84%E0%BC%8B%E0%BD%A0%E0%BD%95%E0%BD%A2%E0%BC%8B%E0%BD%A0%E0%BD%86%E0%BD%BC%E0%BD%A3%E0%BC%8B "སྙིང་འཕར་འཆོལ་ – Tibetan") - [Bosanski](https://bs.wikipedia.org/wiki/Aritmija "Aritmija – Bosnian") - [Català](https://ca.wikipedia.org/wiki/Arr%C3%ADtmia "Arrítmia – Catalan") - [کوردی](https://ckb.wikipedia.org/wiki/%D9%84%DB%8E%D8%AF%D8%A7%D9%86%DB%8C_%D8%AF%DA%B5_%D8%A8%DB%95_%D9%86%D8%A7%D8%AA%DB%95%D9%88%D8%A7%D9%88%DB%8C "لێدانی دڵ بە ناتەواوی – Central Kurdish") - [Čeština](https://cs.wikipedia.org/wiki/Srde%C4%8Dn%C3%AD_arytmie "Srdeční arytmie – Czech") - [Dansk](https://da.wikipedia.org/wiki/Arytmi "Arytmi – Danish") - [Deutsch](https://de.wikipedia.org/wiki/Herzrhythmusst%C3%B6rung "Herzrhythmusstörung – German") - [Ελληνικά](https://el.wikipedia.org/wiki/%CE%91%CF%81%CF%81%CF%85%CE%B8%CE%BC%CE%AF%CE%B1 "Αρρυθμία – Greek") - [Esperanto](https://eo.wikipedia.org/wiki/Kora_misritmo "Kora misritmo – Esperanto") - [Español](https://es.wikipedia.org/wiki/Trastorno_del_ritmo_card%C3%ADaco "Trastorno del ritmo cardíaco – Spanish") - [Eesti](https://et.wikipedia.org/wiki/S%C3%BCdame_r%C3%BCtmih%C3%A4ired "Südame rütmihäired – Estonian") - [Euskara](https://eu.wikipedia.org/wiki/Arritmia "Arritmia – Basque") - [فارسی](https://fa.wikipedia.org/wiki/%D8%A2%D8%B1%DB%8C%D8%AA%D9%85%DB%8C_%D9%82%D9%84%D8%A8 "آریتمی قلب – Persian") - [Suomi](https://fi.wikipedia.org/wiki/Rytmih%C3%A4iri%C3%B6 "Rytmihäiriö – Finnish") - [Français](https://fr.wikipedia.org/wiki/Trouble_du_rythme_cardiaque "Trouble du rythme cardiaque – French") - [Gaeilge](https://ga.wikipedia.org/wiki/Neamhrithimeacht "Neamhrithimeacht – Irish") - [Galego](https://gl.wikipedia.org/wiki/Trastornos_do_ritmo_card%C3%ADaco "Trastornos do ritmo cardíaco – Galician") - [עברית](https://he.wikipedia.org/wiki/%D7%94%D7%A4%D7%A8%D7%A2%D7%AA_%D7%A7%D7%A6%D7%91 "הפרעת קצב – Hebrew") - [Hrvatski](https://hr.wikipedia.org/wiki/Aritmija "Aritmija – Croatian") - [Magyar](https://hu.wikipedia.org/wiki/Sz%C3%ADvritmuszavar "Szívritmuszavar – Hungarian") - [Հայերեն](https://hy.wikipedia.org/wiki/%D4%B1%D5%BC%D5%AB%D5%A9%D5%B4%D5%AB%D5%A1 "Առիթմիա – Armenian") - [Bahasa Indonesia](https://id.wikipedia.org/wiki/Aritmia "Aritmia – Indonesian") - [ГӀалгӀай](https://inh.wikipedia.org/wiki/%D0%94%D0%B5%D0%B3%D0%B0_%D1%85%D0%B0%D1%80%D1%86%D0%B3%D0%B0%D1%80%D1%82 "Дега харцгарт – Ingush") - [Italiano](https://it.wikipedia.org/wiki/Aritmia "Aritmia – Italian") - [日本語](https://ja.wikipedia.org/wiki/%E4%B8%8D%E6%95%B4%E8%84%88 "不整脈 – Japanese") - [ქართული](https://ka.wikipedia.org/wiki/%E1%83%90%E1%83%A0%E1%83%98%E1%83%97%E1%83%9B%E1%83%98%E1%83%90 "არითმია – Georgian") - [Қазақша](https://kk.wikipedia.org/wiki/%D0%A2%D1%8B%D0%BD%D1%8B%D1%81_%D0%B0%D0%BB%D1%83_%D0%B0%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F%D1%81%D1%8B "Тыныс алу аритмиясы – Kazakh") - [한국어](https://ko.wikipedia.org/wiki/%EB%B6%80%EC%A0%95%EB%A7%A5 "부정맥 – Korean") - [Latina](https://la.wikipedia.org/wiki/Arrhythmia_cordis "Arrhythmia cordis – Latin") - [Lombard](https://lmo.wikipedia.org/wiki/Aritmia "Aritmia – Lombard") - [Lietuvių](https://lt.wikipedia.org/wiki/Aritmija "Aritmija – Lithuanian") - [Latviešu](https://lv.wikipedia.org/wiki/Sirds_aritmija "Sirds aritmija – Latvian") - [മലയാളം](https://ml.wikipedia.org/wiki/%E0%B4%85%E0%B4%A4%E0%B4%BE%E0%B4%B3%E0%B4%A4 "അതാളത – Malayalam") - [Bahasa Melayu](https://ms.wikipedia.org/wiki/Disritmia_jantung "Disritmia jantung – Malay") - [Plattdüütsch](https://nds.wikipedia.org/wiki/Hartrhythmusst%C3%B6ren "Hartrhythmusstören – Low German") - [नेपाल भाषा](https://new.wikipedia.org/wiki/%E0%A4%95%E0%A4%BE%E0%A4%B0%E0%A5%8D%E0%A4%A6%E0%A4%BF%E0%A4%AF%E0%A4%BE%E0%A4%95_%E0%A4%85%E0%A4%B0%E0%A4%BF%E0%A4%A6%E0%A4%AE%E0%A4%BF%E0%A4%AF%E0%A4%BE "कार्दियाक अरिदमिया – Newari") - [Nederlands](https://nl.wikipedia.org/wiki/Hartritmestoornis "Hartritmestoornis – Dutch") - [Norsk nynorsk](https://nn.wikipedia.org/wiki/Hjartearytmi "Hjartearytmi – Norwegian Nynorsk") - [Norsk bokmål](https://no.wikipedia.org/wiki/Arytmi "Arytmi – Norwegian Bokmål") - [ଓଡ଼ିଆ](https://or.wikipedia.org/wiki/%E0%AC%85%E0%AC%A8%E0%AC%BF%E0%AD%9F%E0%AC%AE%E0%AC%BF%E0%AC%A4_%E0%AC%B9%E0%AD%83%E0%AC%A4%E0%AD%8D_%E0%AC%B8%E0%AD%8D%E0%AC%AA%E0%AC%A8%E0%AD%8D%E0%AC%A6%E0%AC%A8 "ଅନିୟମିତ ହୃତ୍ ସ୍ପନ୍ଦନ – Odia") - [Kapampangan](https://pam.wikipedia.org/wiki/Cardiac_arrhythmia "Cardiac arrhythmia – Pampanga") - [Polski](https://pl.wikipedia.org/wiki/Zaburzenia_rytmu_serca "Zaburzenia rytmu serca – Polish") - [پښتو](https://ps.wikipedia.org/wiki/%D8%AF_%D8%B2%DA%93%D9%87_%D8%A7%D8%B1%DB%90%D8%AA%D9%85%D9%8A%D8%A7 "د زړه ارېتميا – Pashto") - [Português](https://pt.wikipedia.org/wiki/Arritmia_card%C3%ADaca "Arritmia cardíaca – Portuguese") - [Română](https://ro.wikipedia.org/wiki/Aritmie_cardiac%C4%83 "Aritmie cardiacă – Romanian") - [Русский](https://ru.wikipedia.org/wiki/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F_%D1%81%D0%B5%D1%80%D0%B4%D1%86%D0%B0 "Аритмия сердца – Russian") - [Sicilianu](https://scn.wikipedia.org/wiki/Aritmia "Aritmia – Sicilian") - [Srpskohrvatski / српскохрватски](https://sh.wikipedia.org/wiki/Aritmija "Aritmija – Serbo-Croatian") - [Simple English](https://simple.wikipedia.org/wiki/Arrhythmia "Arrhythmia – Simple English") - [Slovenčina](https://sk.wikipedia.org/wiki/Arytmia "Arytmia – Slovak") - [Slovenščina](https://sl.wikipedia.org/wiki/Sr%C4%8Dna_aritmija "Srčna aritmija – Slovenian") - [Српски / srpski](https://sr.wikipedia.org/wiki/Lupanje_srca "Lupanje srca – Serbian") - [Svenska](https://sv.wikipedia.org/wiki/Arytmi "Arytmi – Swedish") - [தமிழ்](https://ta.wikipedia.org/wiki/%E0%AE%87%E0%AE%A4%E0%AE%AF_%E0%AE%87%E0%AE%B2%E0%AE%AF%E0%AE%AE%E0%AE%BF%E0%AE%A9%E0%AF%8D%E0%AE%AE%E0%AF%88 "இதய இலயமின்மை – Tamil") - [Тоҷикӣ](https://tg.wikipedia.org/wiki/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F%D0%B8_%D0%B4%D0%B8%D0%BB "Аритмияи дил – Tajik") - [ไทย](https://th.wikipedia.org/wiki/%E0%B8%AB%E0%B8%B1%E0%B8%A7%E0%B9%83%E0%B8%88%E0%B9%80%E0%B8%95%E0%B9%89%E0%B8%99%E0%B8%9C%E0%B8%B4%E0%B8%94%E0%B8%88%E0%B8%B1%E0%B8%87%E0%B8%AB%E0%B8%A7%E0%B8%B0 "หัวใจเต้นผิดจังหวะ – Thai") - [Türkçe](https://tr.wikipedia.org/wiki/Aritmi "Aritmi – Turkish") - [Татарча / tatarça](https://tt.wikipedia.org/wiki/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D0%B8%D1%8F "Аритмия – Tatar") - [ئۇيغۇرچە / Uyghurche](https://ug.wikipedia.org/wiki/%D9%8A%DB%88%D8%B1%DB%95%D9%83_%D8%B1%D9%89%D8%AA%D9%89%D9%85%D8%B3%D9%89%D8%B2%D9%84%D9%89%D9%82%D9%89 "يۈرەك رىتىمسىزلىقى – Uyghur") - [Українська](https://uk.wikipedia.org/wiki/%D0%90%D1%80%D0%B8%D1%82%D0%BC%D1%96%D1%97_%D1%81%D0%B5%D1%80%D1%86%D1%8F "Аритмії серця – Ukrainian") - [اردو](https://ur.wikipedia.org/wiki/%D8%A8%DB%92_%D8%A2%DB%81%D9%86%DA%AF%DB%8C "بے آہنگی – Urdu") - [Oʻzbekcha / ўзбекча](https://uz.wikipedia.org/wiki/Aritmiya "Aritmiya – Uzbek") - [Tiếng Việt](https://vi.wikipedia.org/wiki/R%E1%BB%91i_lo%E1%BA%A1n_nh%E1%BB%8Bp_tim "Rối loạn nhịp tim – Vietnamese") - [吴语](https://wuu.wikipedia.org/wiki/%E5%BF%83%E5%BE%8B%E5%A4%B1%E5%B8%B8 "心律失常 – Wu") - [粵語](https://zh-yue.wikipedia.org/wiki/%E5%BF%83%E5%BE%8B%E4%B8%8D%E6%AD%A3 "心律不正 – Cantonese") - [中文](https://zh.wikipedia.org/wiki/%E5%BF%83%E5%BE%8B%E4%B8%8D%E6%95%B4 "心律不整 – Chinese") [Edit links](https://www.wikidata.org/wiki/Special:EntityPage/Q189331#sitelinks-wikipedia "Edit interlanguage links") - 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[Wikimedia Commons](https://commons.wikimedia.org/wiki/Category:Cardiac_arrhythmias) - [Wikidata item](https://www.wikidata.org/wiki/Special:EntityPage/Q189331 "Structured data on this page hosted by Wikidata [g]") Appearance move to sidebar hide From Wikipedia, the free encyclopedia Group of medical conditions characterized by irregular heartbeat This article is about the irregular heartbeat. For the skin condition, see [erythema](https://en.wikipedia.org/wiki/Erythema "Erythema"). For other uses, see [Arrhythmia (disambiguation)](https://en.wikipedia.org/wiki/Arrhythmia_\(disambiguation\) "Arrhythmia (disambiguation)"). Not to be confused with [Beat deafness](https://en.wikipedia.org/wiki/Beat_deafness "Beat deafness"). Medical condition \| Arrhythmia \| \| \|---\|---\| \| Other names \| Cardiac arrhythmia, heart arrhythmia, dysrhythmia, irregular heartbeat \| \| [![](https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/Ventricular_fibrillation.png/330px-Ventricular_fibrillation.png)](https://en.wikipedia.org/wiki/File:Ventricular_fibrillation.png) \| \| \| [Ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") (VF) showing disorganized electrical activity producing a spiked tracing on an [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") (ECG) \| \| \| [Specialty](https://en.wikipedia.org/wiki/Medical_specialty "Medical specialty") \| [Cardiology](https://en.wikipedia.org/wiki/Cardiology "Cardiology") \| \| [Symptoms](https://en.wikipedia.org/wiki/Signs_and_symptoms "Signs and symptoms") \| [Palpitations](https://en.wikipedia.org/wiki/Palpitations "Palpitations"), [dizziness](https://en.wikipedia.org/wiki/Dizziness "Dizziness") or [lightheadedness](https://en.wikipedia.org/wiki/Presyncope "Presyncope"), [passing out](https://en.wikipedia.org/wiki/Syncope_\(medicine\) "Syncope (medicine)"), [shortness of breath](https://en.wikipedia.org/wiki/Shortness_of_breath "Shortness of breath"), [chest pain](https://en.wikipedia.org/wiki/Chest_pain "Chest pain"),[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) [decreased level of consciousness](https://en.wikipedia.org/wiki/Decreased_level_of_consciousness "Decreased level of consciousness") \| \| [Complications](https://en.wikipedia.org/wiki/Complication_\(medicine\) "Complication (medicine)") \| [Stroke](https://en.wikipedia.org/wiki/Stroke "Stroke"), [heart failure](https://en.wikipedia.org/wiki/Heart_failure "Heart failure")[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2)[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3), [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest") \| \| Usual onset \| Older age[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) \| \| Types \| [Extra beats](https://en.wikipedia.org/wiki/Premature_heart_beat "Premature heart beat"), [supraventricular tachycardias](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia"), [ventricular arrhythmias](https://en.wikipedia.org/wiki/Ventricular_arrhythmia "Ventricular arrhythmia"), [bradyarrhythmias](https://en.wikipedia.org/wiki/Bradyarrhythmia "Bradyarrhythmia")[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) \| \| [Causes](https://en.wikipedia.org/wiki/Cause_\(medicine\) "Cause (medicine)") \| Problems with the [electrical conduction system of the heart](https://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart "Electrical conduction system of the heart")[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) \| \| [Diagnostic method](https://en.wikipedia.org/wiki/Medical_diagnosis "Medical diagnosis") \| [Electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram"), [Holter monitor](https://en.wikipedia.org/wiki/Holter_monitor "Holter monitor")[\[5\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Diag-5) \| \| Treatment \| Medications, medical procedures ([pacemaker](https://en.wikipedia.org/wiki/Pacemaker "Pacemaker")), surgery[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) \| \| Frequency \| Millions[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) \| ![](https://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Gnome-mime-sound-openclipart.svg/60px-Gnome-mime-sound-openclipart.svg.png) [Emma's irregular heartbeat](https://en.wikipedia.org/wiki/File:Emma%27s_irregular_heartbeat.wav "File:Emma's irregular heartbeat.wav") Heart sounds of a girl experiencing arrhythmia after exercising. *** Problems playing this file? See [media help](https://en.wikipedia.org/wiki/Help:Media "Help:Media"). Arrhythmias, also known as cardiac arrhythmias, are irregularities in the [heartbeat](https://en.wikipedia.org/wiki/Cardiac_cycle "Cardiac cycle"), including when it is too fast or too slow.[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) Essentially, this is anything but [normal sinus rhythm](https://en.wikipedia.org/wiki/Normal_sinus_rhythm "Normal sinus rhythm"). A resting [heart rate](https://en.wikipedia.org/wiki/Heart_rate "Heart rate") that is too fast – above 100 beats per minute in adults – is called [tachycardia](https://en.wikipedia.org/wiki/Tachycardia "Tachycardia"), and a resting heart rate that is too slow – below 60 beats per minute – is called [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia").[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) Some types of arrhythmias have no [symptoms](https://en.wikipedia.org/wiki/Symptoms "Symptoms").[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) Symptoms, when present, may include [palpitations](https://en.wikipedia.org/wiki/Palpitations "Palpitations") or feeling a pause between heartbeats.[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) In more serious cases, there may be [lightheadedness](https://en.wikipedia.org/wiki/Presyncope "Presyncope"), [passing out](https://en.wikipedia.org/wiki/Syncope_\(medicine\) "Syncope (medicine)"), [shortness of breath](https://en.wikipedia.org/wiki/Shortness_of_breath "Shortness of breath"), [chest pain](https://en.wikipedia.org/wiki/Chest_pain "Chest pain"), or [decreased level of consciousness](https://en.wikipedia.org/wiki/Decreased_level_of_consciousness "Decreased level of consciousness").[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) While most cases of arrhythmia are not serious, some predispose a person to complications such as [stroke](https://en.wikipedia.org/wiki/Stroke "Stroke") or [heart failure](https://en.wikipedia.org/wiki/Heart_failure "Heart failure").[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2)[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Others may result in [sudden death](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Arrhythmias are often categorized into four groups: [extra beats](https://en.wikipedia.org/wiki/Premature_heart_beat "Premature heart beat"), [supraventricular tachycardias](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia"), [ventricular arrhythmias](https://en.wikipedia.org/wiki/Ventricular_arrhythmia "Ventricular arrhythmia") and [bradyarrhythmias](https://en.wikipedia.org/wiki/Bradyarrhythmia "Bradyarrhythmia").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Extra beats include [premature atrial contractions](https://en.wikipedia.org/wiki/Premature_atrial_contraction "Premature atrial contraction"), [premature ventricular contractions](https://en.wikipedia.org/wiki/Premature_ventricular_contraction "Premature ventricular contraction") and [premature junctional contractions](https://en.wikipedia.org/wiki/Premature_junctional_contractions "Premature junctional contractions").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Supraventricular tachycardias include [atrial fibrillation](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation"), [atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter") and [paroxysmal supraventricular tachycardia](https://en.wikipedia.org/wiki/Paroxysmal_supraventricular_tachycardia "Paroxysmal supraventricular tachycardia").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Ventricular arrhythmias include [ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") and [ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3)[\[7\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Martin2012-7) Bradyarrhythmias are due to [sinus node dysfunction](https://en.wikipedia.org/wiki/Sinus_node_dysfunction "Sinus node dysfunction") or [atrioventricular conduction disturbances](https://en.wikipedia.org/wiki/Atrioventricular_block "Atrioventricular block").[\[8\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-8) Arrhythmias are due to problems with the [electrical conduction system of the heart](https://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart "Electrical conduction system of the heart").[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) A number of tests can help with diagnosis, including an [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") (ECG) and [Holter monitor](https://en.wikipedia.org/wiki/Holter_monitor "Holter monitor").[\[5\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Diag-5) Many arrhythmias can be effectively treated.[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) Treatments may include medications, medical procedures such as inserting a [pacemaker](https://en.wikipedia.org/wiki/Pacemaker "Pacemaker"), and surgery.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Medications for a fast heart rate may include [beta blockers](https://en.wikipedia.org/wiki/Beta_blockers "Beta blockers"), or [antiarrhythmic agents](https://en.wikipedia.org/wiki/Antiarrhythmic_agent "Antiarrhythmic agent") such as [procainamide](https://en.wikipedia.org/wiki/Procainamide "Procainamide"), which attempt to restore a normal heart rhythm.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) This latter group may have more significant side effects, especially if taken for a long period of time.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Pacemakers are often used for slow heart rates.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Those with an irregular heartbeat are often treated with [blood thinners](https://en.wikipedia.org/wiki/Blood_thinner "Blood thinner") to reduce the risk of complications.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Those who have severe symptoms from an arrhythmia or are medically unstable may receive urgent treatment with a [controlled electric shock](https://en.wikipedia.org/wiki/Electric_shock#Medical_uses "Electric shock") in the form of [cardioversion](https://en.wikipedia.org/wiki/Cardioversion "Cardioversion") or [defibrillation](https://en.wikipedia.org/wiki/Defibrillation "Defibrillation").[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Arrhythmia affects millions of people.[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population.[\[9\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Zoni2014-9) Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990.[\[10\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-GDB2013-10) However, in most recent cases concerning the SARS-CoV‑2 pandemic, cardiac arrhythmias are commonly developed and associated with high morbidity and mortality among patients hospitalized with the COVID-19 infection, due to the infection's ability to cause myocardial injury.[\[11\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-11) [Sudden cardiac death](https://en.wikipedia.org/wiki/Sudden_cardiac_death "Sudden cardiac death") is the cause of about half of deaths due to [cardiovascular disease](https://en.wikipedia.org/wiki/Cardiovascular_disease "Cardiovascular disease") and about 15% of all deaths globally.[\[12\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Meh2007-12) About 80% of sudden cardiac death is the result of ventricular arrhythmias.[\[12\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Meh2007-12) Arrhythmias may occur at any age but are more common among older people.[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) Arrhythmias may also occur in children; however, the normal range for the heart rate varies with age.[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) ## Classification \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=1 "Edit section: Classification")\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/7/77/De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png/500px-De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png)](https://en.wikipedia.org/wiki/File:De-Atrial_ventricular_\(CardioNetworks_ECGpedia\).png) Broad classification of arrhythmias according to region of heart required to sustain the rhythm Arrhythmia may be classified by rate ([tachycardia](https://en.wikipedia.org/wiki/Tachycardia "Tachycardia"), [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia")), mechanism (automaticity, re-entry, triggered) or duration (isolated [premature beats](https://en.wikipedia.org/wiki/Premature_heart_beat "Premature heart beat"); couplets; runs, that is 3 or more beats; non-sustained = less than 30 seconds or sustained = over 30 seconds).\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Arrhythmias are also classified by site of origin:\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] ### Atrial arrhythmia \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=2 "Edit section: Atrial arrhythmia")\] - [Sinus bradycardia](https://en.wikipedia.org/wiki/Sinus_bradycardia "Sinus bradycardia") - [Sinus arrhythmia](https://en.wikipedia.org/wiki/Sinus_arrhythmia "Sinus arrhythmia") - [Sinus tachycardia](https://en.wikipedia.org/wiki/Sinus_tachycardia "Sinus tachycardia") - [Premature atrial contractions (PACs)](https://en.wikipedia.org/wiki/Premature_atrial_contraction "Premature atrial contraction") - [Wandering atrial pacemaker](https://en.wikipedia.org/wiki/Wandering_pacemaker "Wandering pacemaker") - [Atrial tachycardia](https://en.wikipedia.org/wiki/Atrial_tachycardia "Atrial tachycardia") - [Multifocal atrial tachycardia](https://en.wikipedia.org/wiki/Multifocal_atrial_tachycardia "Multifocal atrial tachycardia") - [Supraventricular tachycardia (SVT)](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia") - [Atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter") - [Atrial fibrillation (Afib)](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation") - [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") ### Junctional arrhythmia \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=3 "Edit section: Junctional arrhythmia")\] - [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") - [Junctional rhythm](https://en.wikipedia.org/wiki/Junctional_rhythm "Junctional rhythm") - [Junctional tachycardia](https://en.wikipedia.org/wiki/Junctional_tachycardia "Junctional tachycardia") - [Premature junctional contraction](https://en.wikipedia.org/wiki/Premature_junctional_contraction "Premature junctional contraction") ### Ventricular arrhythmia \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=4 "Edit section: Ventricular arrhythmia")\] - [Premature ventricular contractions](https://en.wikipedia.org/wiki/Premature_ventricular_contraction "Premature ventricular contraction") (PVCs), sometimes called ventricular extra beats (VEBs) - Premature ventricular beats occurring after every normal beat are termed [ventricular bigeminy](https://en.wikipedia.org/wiki/Ventricular_bigeminy "Ventricular bigeminy") - PVCs that occur at intervals of 2 normal beats to 1 PVC, or 1 normal beat to 2 PVCs, are termed "PVCs in trigeminy"[\[13\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Farzam-13) - Groups of three premature ventricular beats are called triplets and are considered a brief run of [non-sustained ventricular tachycardia](https://en.wikipedia.org/wiki/Non-sustained_ventricular_tachycardia "Non-sustained ventricular tachycardia") (NSVT); if the grouping lasts for more than 30 seconds, it is considered sustained [ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia") (VT).[\[14\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-wagnerNSVT-14) - [Accelerated idioventricular rhythm](https://en.wikipedia.org/wiki/Accelerated_idioventricular_rhythm "Accelerated idioventricular rhythm") - [Monomorphic ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia") - [Polymorphic ventricular tachycardia](https://en.wikipedia.org/wiki/Polymorphic_ventricular_tachycardia "Polymorphic ventricular tachycardia") - [Ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") - [Torsades de pointes](https://en.wikipedia.org/wiki/Torsades_de_pointes "Torsades de pointes") - [Arrhythmogenic right ventricular dysplasia](https://en.wikipedia.org/wiki/Arrhythmogenic_right_ventricular_dysplasia "Arrhythmogenic right ventricular dysplasia") - [Re-entry ventricular arrhythmia](https://en.wikipedia.org/wiki/Re-entry_ventricular_arrhythmia "Re-entry ventricular arrhythmia") ### Heart blocks \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=5 "Edit section: Heart blocks")\] [Heart blocks](https://en.wikipedia.org/wiki/Heart_block "Heart block") are also known as [AV](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node") blocks, because the vast majority of them arise from pathology at the [atrioventricular node](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node"). They are the most common causes of bradycardia:\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] - [First-degree heart block](https://en.wikipedia.org/wiki/First-degree_heart_block "First-degree heart block"), which manifests as PR prolongation - [Second-degree heart block](https://en.wikipedia.org/wiki/Second-degree_heart_block "Second-degree heart block") - [Type 1 Second degree heart block](https://en.wikipedia.org/wiki/Type_1_Second_degree_heart_block "Type 1 Second degree heart block"), also known as [Mobitz I](https://en.wikipedia.org/wiki/Mobitz_I "Mobitz I") or [Wenckebach](https://en.wikipedia.org/wiki/Wenckebach "Wenckebach") - [Type 2 Second degree heart block](https://en.wikipedia.org/wiki/Type_2_Second_degree_heart_block "Type 2 Second degree heart block"), also known as [Mobitz II](https://en.wikipedia.org/wiki/Mobitz_II "Mobitz II") - [Third-degree heart block](https://en.wikipedia.org/wiki/Third-degree_heart_block "Third-degree heart block"), also known as [complete heart block](https://en.wikipedia.org/wiki/Complete_heart_block "Complete heart block") First, second, and third-degree blocks also can occur at the level of the sinoatrial junction. This is referred to as [sinoatrial block](https://en.wikipedia.org/wiki/Sinoatrial_block "Sinoatrial block") typically manifesting with various degrees and patterns of [sinus bradycardia](https://en.wikipedia.org/wiki/Sinus_bradycardia "Sinus bradycardia").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] ### Sudden arrhythmic death syndrome \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=6 "Edit section: Sudden arrhythmic death syndrome")\] [Sudden arrhythmic death syndrome](https://en.wikipedia.org/wiki/Sudden_arrhythmic_death_syndrome "Sudden arrhythmic death syndrome") (SADS), is a term used as part of sudden unexpected death syndrome to describe sudden [death](https://en.wikipedia.org/wiki/Death "Death") because of [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest") occasioned by an arrhythmia in the presence or absence of any structural heart disease on autopsy. The most common cause of sudden death in the US is [coronary artery disease](https://en.wikipedia.org/wiki/Coronary_artery_disease "Coronary artery disease") specifically because of poor oxygenation of the heart muscle, that is [myocardial ischemia](https://en.wikipedia.org/wiki/Myocardial_ischemia "Myocardial ischemia") or a [heart attack](https://en.wikipedia.org/wiki/Myocardial_infarction "Myocardial infarction")[\[15\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-15) Approximately 180,000 to 250,000 people die suddenly of this cause every year in the US. SADS may occur from other causes. There are many inherited conditions and heart diseases that can affect young people which can subsequently cause sudden death without advance symptoms.[\[16\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-16) Causes of SADS in young people include [viral myocarditis](https://en.wikipedia.org/wiki/Viral_myocarditis "Viral myocarditis"), [long QT syndrome](https://en.wikipedia.org/wiki/Long_QT_syndrome "Long QT syndrome"), [Brugada syndrome](https://en.wikipedia.org/wiki/Brugada_syndrome "Brugada syndrome"), [Catecholaminergic polymorphic ventricular tachycardia](https://en.wikipedia.org/wiki/Catecholaminergic_polymorphic_ventricular_tachycardia "Catecholaminergic polymorphic ventricular tachycardia"), [hypertrophic cardiomyopathy](https://en.wikipedia.org/wiki/Hypertrophic_cardiomyopathy "Hypertrophic cardiomyopathy") and [arrhythmogenic right ventricular dysplasia](https://en.wikipedia.org/wiki/Arrhythmogenic_right_ventricular_dysplasia "Arrhythmogenic right ventricular dysplasia").[\[17\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Chugh-2008-17)[\[18\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-18) ### Fetal arrhythmia \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=7 "Edit section: Fetal arrhythmia")\] Arrhythmias may also occur in the [fetus](https://en.wikipedia.org/wiki/Fetus "Fetus").[\[19\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Batra-19) The normal heart rate of the fetus is between 110 and 160 beats per minute. Any rhythm beyond these limits is abnormal and classed as a fetal arrhythmia. These are mainly the result of premature atrial contractions, usually give no symptoms, and have little consequence. However, around one percent of these will be the result of significant structural damage to the heart.[\[19\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Batra-19) ## Signs and symptoms \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=8 "Edit section: Signs and symptoms")\] The term cardiac arrhythmia covers a very large number of very different conditions.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] The most common symptom of arrhythmia is an awareness of an abnormal heartbeat, called [palpitations](https://en.wikipedia.org/wiki/Palpitation "Palpitation"). These may be infrequent, frequent, or continuous. Some of these arrhythmias are harmless (though [distracting](https://en.wikipedia.org/wiki/Distracting "Distracting") for patients) but some of them predispose to adverse outcomes. Arrhythmias also cause [chest pain](https://en.wikipedia.org/wiki/Chest_pain "Chest pain") and [shortness of breath](https://en.wikipedia.org/wiki/Shortness_of_breath "Shortness of breath").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Some arrhythmias do not cause symptoms and are not associated with increased mortality. However, some asymptomatic arrhythmias are associated with adverse events. Examples include a higher risk of blood clotting within the heart and a higher risk of insufficient blood being transported to the heart because of a weak heartbeat. Other increased risks are of [embolization](https://en.wikipedia.org/wiki/Embolization "Embolization") and stroke, heart failure, and sudden cardiac death.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] If an arrhythmia results in a heartbeat that is too fast, too slow, or too weak to supply the body's needs, this manifests as lower blood pressure and may cause lightheadedness, dizziness, syncope, loss of consciousness, [coma](https://en.wikipedia.org/wiki/Coma "Coma"), [persistent vegetative state](https://en.wikipedia.org/wiki/Persistent_vegetative_state "Persistent vegetative state"), or brain death due to insufficient supply of blood and oxygen to the brain.[\[20\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-20) Some types of arrhythmia result in [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest"), or sudden death.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Medical assessment of the abnormality using an [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") is one way to diagnose and assess the risk of any given arrhythmia.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] ## Mechanism \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=9 "Edit section: Mechanism")\] Cardiac arrhythmia are caused by one of two major mechanisms. The first of arrhythmia is a result of enhanced or abnormal [impulse](https://en.wikipedia.org/wiki/Cardiac_action_potential "Cardiac action potential") formation originating at the [pacemaker](https://en.wikipedia.org/wiki/Cardiac_pacemaker "Cardiac pacemaker") or the [His](https://en.wikipedia.org/wiki/Bundle_of_His "Bundle of His")\-[Purkinje](https://en.wikipedia.org/wiki/Purkinje_fibers "Purkinje fibers") network. The second is due to [re-entry](https://en.wikipedia.org/wiki/Arrhythmia#Re-entry) conduction disturbances.[\[21\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Antzelevitch_2011-21) ## Diagnostic \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=10 "Edit section: Diagnostic")\] Cardiac arrhythmia is often first detected by simple but nonspecific means: [auscultation](https://en.wikipedia.org/wiki/Auscultation "Auscultation") of the heartbeat with a [stethoscope](https://en.wikipedia.org/wiki/Stethoscope "Stethoscope"), or feeling for peripheral [pulses](https://en.wikipedia.org/wiki/Pulse "Pulse"). These cannot usually diagnose specific arrhythmia but can give a general indication of the heart rate and whether it is regular or irregular. Not all the electrical impulses of the heart produce audible or palpable beats; in many cardiac arrhythmias, the premature or abnormal beats do not produce an effective pumping action and are experienced as "skipped" beats.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] The simplest specific diagnostic test for assessment of heart rhythm is the [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") (abbreviated ECG or EKG).[\[22\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-22)[\[23\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-23) A [Holter monitor](https://en.wikipedia.org/wiki/Holter_monitor "Holter monitor") is an EKG recorded over a 24-hour period, to detect arrhythmias that may happen briefly and unpredictably throughout the day.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] A more advanced study of the heart's electrical activity can be performed to assess the source of the [aberrant](https://en.wikipedia.org/wiki/Cardiac_aberration "Cardiac aberration") heart beats. This can be accomplished in an [electrophysiology study](https://en.wikipedia.org/wiki/Electrophysiology_study "Electrophysiology study"), an [endovascular procedure](https://en.wikipedia.org/wiki/Endovascular_procedure "Endovascular procedure") that uses a catheter to "listen" to the electrical activity from within the heart, additionally if the source of the arrhythmias is found, often the abnormal cells can be ablated and the arrhythmia can be permanently corrected. Transesophageal atrial stimulation (TAS) instead uses an electrode inserted through the [esophagus](https://en.wikipedia.org/wiki/Esophagus "Esophagus") to a part where the distance to the posterior wall of the [left atrium](https://en.wikipedia.org/wiki/Left_atrium "Left atrium") is only approximately 5–6 mm (remaining constant in people of different age and weight).[\[24\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-MeigasKaik2008-24) Transesophageal atrial stimulation can differentiate between [atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter"), [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") and orthodromic [atrioventricular reentrant tachycardia](https://en.wikipedia.org/wiki/Atrioventricular_reentrant_tachycardia "Atrioventricular reentrant tachycardia").[\[25\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25) It can also evaluate the risk in people with [Wolff–Parkinson–White syndrome](https://en.wikipedia.org/wiki/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome "Wolff–Parkinson–White syndrome"), as well as terminate [supraventricular tachycardia](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia") caused by [re-entry](https://en.wikipedia.org/wiki/Cardiac_arrhythmia#Re-entry "Cardiac arrhythmia").[\[25\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25) ### Differential diagnosis \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=11 "Edit section: Differential diagnosis")\] #### Normal electrical activity \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=12 "Edit section: Normal electrical activity")\] Main article: [Electrical conduction system of the heart](https://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart "Electrical conduction system of the heart") Each heartbeat originates as an electrical impulse from a small area of tissue in the right [atrium](https://en.wikipedia.org/wiki/Atrium_\(heart\) "Atrium (heart)") of the heart called the [sinus node or sinoatrial node (SA node)](https://en.wikipedia.org/wiki/Sinoatrial_node "Sinoatrial node"). The impulse initially causes both atria to contract, then activates the [atrioventricular node (AV node)](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node"), which is normally the only electrical connection between the atria and the [ventricles](https://en.wikipedia.org/wiki/Ventricle_\(heart\) "Ventricle (heart)") (main pumping chambers). The impulse then spreads through both ventricles via the [bundle of His](https://en.wikipedia.org/wiki/Bundle_of_His "Bundle of His") and the [Purkinje fibers](https://en.wikipedia.org/wiki/Purkinje_fibers "Purkinje fibers") causing a synchronized contraction of the heart muscle and, thus, the pulse.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] In adults, the normal resting heart rate ranges from 60 to 90 beats per minute. The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered normal.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] The term [sinus arrhythmia](https://en.wikipedia.org/wiki/Respiratory_sinus_arrhythmia "Respiratory sinus arrhythmia")[\[26\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-26) refers to a normal phenomenon of alternating mild acceleration and slowing of the heart rate that occurs with breathing in and out respectively. It is usually quite pronounced in children and steadily decreases with age. This can also be present during [meditation](https://en.wikipedia.org/wiki/Meditation "Meditation") breathing exercises that involve deep inhaling and breath holding patterns.[\[27\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-27) #### Bradycardias \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=13 "Edit section: Bradycardias")\] [![](https://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Sinus_pause.PNG/250px-Sinus_pause.PNG)](https://en.wikipedia.org/wiki/File:Sinus_pause.PNG) Normal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm. A slow rhythm (less than 60 beats/min) is labelled [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia"). This may be caused by a slowed signal from the sinus node (sinus bradycardia), by a pause in the normal activity of the sinus node (sinus arrest), or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block). Heart block comes in varying degrees and severity. It may be caused by reversible poisoning of the AV node (with drugs that impair conduction) or by irreversible damage to the node. Bradycardias may also be present in the normally functioning heart of endurance athletes or other well-conditioned persons. Bradycardia may also occur in [some types of seizures](https://en.wikipedia.org/wiki/Ictal_bradycardia "Ictal bradycardia").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] #### Tachycardias \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=14 "Edit section: Tachycardias")\] In adults and children over 15, resting heart rate faster than 100 beats per minute is labeled [tachycardia](https://en.wikipedia.org/wiki/Tachycardia "Tachycardia"). Tachycardia may result in palpitation; however, tachycardia is not necessarily an arrhythmia. Increased heart rate is a normal response to physical exercise or emotional stress. This is mediated by the [sympathetic nervous system](https://en.wikipedia.org/wiki/Sympathetic_nervous_system "Sympathetic nervous system") on the [sinus node](https://en.wikipedia.org/wiki/Sinus_node "Sinus node") and called sinus tachycardia. Other conditions that increase sympathetic nervous system activity in the heart include ingested or injected substances, such as [caffeine](https://en.wikipedia.org/wiki/Caffeine "Caffeine") or [amphetamines](https://en.wikipedia.org/wiki/Amphetamines "Amphetamines"), and an overactive thyroid gland ([hyperthyroidism](https://en.wikipedia.org/wiki/Hyperthyroidism "Hyperthyroidism")) or [anemia](https://en.wikipedia.org/wiki/Anemia "Anemia").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Tachycardia that is not sinus tachycardia usually results from the addition of abnormal impulses to the normal [cardiac cycle](https://en.wikipedia.org/wiki/Cardiac_cycle "Cardiac cycle"). Abnormal impulses can begin by one of three mechanisms: automaticity, re-entry, or triggered activity. A specialized form of re-entry which is both common and problematic is termed fibrillation.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Although the term "tachycardia" has been known for over 160 years, bases for the classification of arrhythmias are still being discussed.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] #### Heart defects \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=15 "Edit section: Heart defects")\] Congenital heart defects are structural or electrical pathway problems in the heart that are present at birth. Anyone can be affected by this because overall health does not play a role in the problem. Problems with the electrical pathway of the heart can cause very fast or even deadly arrhythmias. [Wolff–Parkinson–White syndrome](https://en.wikipedia.org/wiki/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome "Wolff–Parkinson–White syndrome") is due to an extra pathway in the heart that is made up of electrical muscle tissue. This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly. Right [ventricular outflow tract](https://en.wikipedia.org/wiki/Ventricular_outflow_tract "Ventricular outflow tract") tachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals. This defect is due to an electrical node in the right ventricle just before the pulmonary artery. When the node is stimulated, the patient will go into ventricular tachycardia, which does not allow the heart to fill with blood before beating again. [Long QT syndrome](https://en.wikipedia.org/wiki/Long_QT_syndrome "Long QT syndrome") is another complex problem in the heart and has been labeled as an independent factor in mortality. There are multiple methods of treatment for these including cardiac ablations, medication treatment, or lifestyle changes to have less stress and exercise.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] #### Automaticity \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=16 "Edit section: Automaticity")\] Main article: [Automatic tachycardia](https://en.wikipedia.org/wiki/Automatic_tachycardia "Automatic tachycardia") Automaticity refers to a [cardiac muscle](https://en.wikipedia.org/wiki/Cardiac_muscle "Cardiac muscle") cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an [action potential](https://en.wikipedia.org/wiki/Action_potential "Action potential"); however, only some of these cells are designed to routinely trigger heartbeats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His, and Purkinje fibers. The [sinoatrial node](https://en.wikipedia.org/wiki/Sinoatrial_node "Sinoatrial node") is a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heartbeat.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Any part of the heart that initiates an impulse without waiting for the sinoatrial node is called an [ectopic](https://en.wikipedia.org/wiki/Cardiac_ectopy "Cardiac ectopy") focus and is, by definition, a pathological phenomenon. This may cause a single premature beat now and then, or, if the [ectopic focus](https://en.wikipedia.org/wiki/Ectopic_focus "Ectopic focus") fires more often than the sinoatrial node, it can produce a sustained abnormal rhythm. Rhythms produced by an ectopic focus in the atria, or by the [atrioventricular node](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node"), are the least dangerous dysrhythmias; but they can still produce a decrease in the heart's pumping efficiency because the signal reaches the various parts of the heart muscle with different timing than usual and can be responsible for poorly coordinated contraction.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Conditions that increase automaticity include [sympathetic nervous system](https://en.wikipedia.org/wiki/Sympathetic_nervous_system "Sympathetic nervous system") stimulation and [hypoxia](https://en.wikipedia.org/wiki/Hypoxia_\(medical\) "Hypoxia (medical)"). The resulting heart rhythm depends on where the first signal begins: If it is the sinoatrial node, the rhythm remains normal but rapid; if it is an ectopic focus, many types of dysrhythmia may ensue. #### Re-entry \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=17 "Edit section: Re-entry")\] Re-entrant arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping.[\[28\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Wiener-1946-28)[\[29\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Allessie-1976-29) Every cardiac cell can transmit [impulses of excitation](https://en.wikipedia.org/wiki/Autowave "Autowave") in every direction but will do so only once within a short time. Normally, the [action potential](https://en.wikipedia.org/wiki/Action_potential "Action potential") impulse will spread through the heart quickly enough that each cell will respond only once. However, if there is some essential heterogeneity of [refractory period](https://en.wikipedia.org/wiki/Refractory_period_\(physiology\) "Refractory period (physiology)") or if conduction is abnormally slow in some areas (for example in heart damage) so the myocardial cells are unable to activate the fast sodium channel, part of the impulse will arrive late and potentially be treated as a new impulse. Depending on the timing, this can produce a sustained abnormal circuit rhythm. As a sort of re-entry, vortices of excitation in the myocardium ([autowave vortices](https://en.wikipedia.org/wiki/Autowave "Autowave")) are considered to be the main mechanism of life-threatening cardiac arrhythmias.[\[30\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-b-Mandel-1995-30) In particular, the [autowave reverberator](https://en.wikipedia.org/wiki/Autowave_reverberator "Autowave reverberator") is common in the thin walls of the atria, sometimes resulting in [atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter"). Re-entry is also responsible for most [paroxysmal supraventricular tachycardia](https://en.wikipedia.org/wiki/Paroxysmal_supraventricular_tachycardia "Paroxysmal supraventricular tachycardia"), and dangerous [ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia"). These types of re-entry circuits are different from [WPW](https://en.wikipedia.org/wiki/WPW "WPW") syndromes, which utilize abnormal conduction pathways. Although [omega-3 fatty acids](https://en.wikipedia.org/wiki/Omega-3_fatty_acid "Omega-3 fatty acid") from [fish oil](https://en.wikipedia.org/wiki/Fish_oil "Fish oil") can be protective against arrhythmias, they can facilitate re-entrant arrhythmias.[\[31\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Coronel-2007-31) #### Fibrillation \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=18 "Edit section: Fibrillation")\] When an entire chamber of the heart is involved in multiple micro-re-entry circuits and is, therefore, quivering with chaotic electrical impulses, it is said to be in fibrillation. Fibrillation can affect the atrium ([atrial fibrillation](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation")) or the ventricle ([ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation")): ventricular fibrillation is imminently life-threatening. - Atrial fibrillation affects the upper chambers of the heart, known as the [atria](https://en.wikipedia.org/wiki/Atrium_\(heart\) "Atrium (heart)"). Atrial fibrillation may be due to serious underlying medical conditions and should be evaluated by a [physician](https://en.wikipedia.org/wiki/Physician "Physician"). It is not typically a medical emergency. - Ventricular fibrillation occurs in the [ventricles](https://en.wikipedia.org/wiki/Ventricle_\(heart\) "Ventricle (heart)") (lower chambers) of the heart; it is always a medical emergency. If left untreated, [ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") (VF, or V-fib) can lead to death within minutes. When a heart goes into V-fib, effective pumping of the blood stops. V-fib is considered a form of [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest"). An affected individual will not survive unless [cardiopulmonary resuscitation](https://en.wikipedia.org/wiki/Cardiopulmonary_resuscitation "Cardiopulmonary resuscitation") (CPR) and [defibrillation](https://en.wikipedia.org/wiki/Defibrillation "Defibrillation") are provided immediately. CPR can prolong the survival of the [brain](https://en.wikipedia.org/wiki/Brain "Brain") in the lack of a normal pulse, but defibrillation is the only intervention that can restore a healthy heart rhythm. Defibrillation is performed by applying an electric shock to the heart, which resets the cells, permitting a normal beat to re-establish itself. #### Triggered beats \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=19 "Edit section: Triggered beats")\] Triggered beats occur when problems at the level of the ion channels in individual heart cells result in abnormal propagation of electrical activity and can lead to a sustained abnormal rhythm. They are relatively rare and can result from the action of anti-arrhythmic drugs, or after [depolarizations](https://en.wikipedia.org/wiki/Depolarization "Depolarization").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] ## Management \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=20 "Edit section: Management")\] The method of cardiac rhythm management depends firstly on whether the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro- or cryo-cautery.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] In the United States, people admitted to the hospital with cardiac arrhythmia and conduction disorders with and without complications were admitted to the intensive care unit more than half the time in 2011.[\[32\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-32) ### Physical maneuvers \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=21 "Edit section: Physical maneuvers")\] Several physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop several arrhythmias that originate above or at the AV node (see main article: [supraventricular tachycardias](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia")). Parasympathetic nervous supply to the heart is via the [vagus nerve](https://en.wikipedia.org/wiki/Vagus_nerve "Vagus nerve"), and these maneuvers are collectively known as [vagal maneuvers](https://en.wikipedia.org/wiki/Vagal_maneuver "Vagal maneuver"). ### Antiarrhythmic drugs \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=22 "Edit section: Antiarrhythmic drugs")\] Main article: [Antiarrhythmic agents](https://en.wikipedia.org/wiki/Antiarrhythmic_agents "Antiarrhythmic agents") There are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes. Although the goal of drug therapy is to prevent arrhythmia, nearly every antiarrhythmic drug has the potential to act as a [pro-arrhythmic](https://en.wikipedia.org/wiki/Pro-arrhythmic "Pro-arrhythmic"), and so must be carefully selected and used under medical supervision. ### Other drugs \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=23 "Edit section: Other drugs")\] Several groups of drugs slow conduction through the heart, without actually preventing an arrhythmia. These drugs can be used to "rate control" a fast rhythm and make it physically tolerable for the patient.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Some arrhythmias promote blood clotting within the heart and increase the risk of embolus and stroke. [Anticoagulant](https://en.wikipedia.org/wiki/Anticoagulant "Anticoagulant") medications such as [warfarin](https://en.wikipedia.org/wiki/Warfarin "Warfarin") and [heparins](https://en.wikipedia.org/wiki/Heparin "Heparin"), and anti-platelet drugs such as [aspirin](https://en.wikipedia.org/wiki/Aspirin "Aspirin") can reduce the risk of clotting. ### Electricity \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=24 "Edit section: Electricity")\] Arrhythmias may also be treated electrically, by applying a shock across the heart – either externally to the chest wall, or internally to the heart via implanted electrodes.[\[33\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-33) [Cardioversion](https://en.wikipedia.org/wiki/Cardioversion "Cardioversion") is either achieved pharmacologically or via the application of a shock synchronized to the underlying heartbeat. It is used for the treatment of supraventricular tachycardias. In elective cardioversion, the recipient is usually sedated or lightly [anesthetized](https://en.wikipedia.org/wiki/Anesthesia "Anesthesia") for the procedure. [Defibrillation](https://en.wikipedia.org/wiki/Defibrillation "Defibrillation") differs in that the shock is not synchronized. It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, more electricity is required for defibrillation than for cardioversion. In most defibrillation, the recipient has lost consciousness so there is no need for sedation. Defibrillation or cardioversion may be accomplished by an [implantable cardioverter-defibrillator](https://en.wikipedia.org/wiki/Implantable_cardioverter-defibrillator "Implantable cardioverter-defibrillator") (ICD). Electrical treatment of arrhythmias also includes [cardiac pacing](https://en.wikipedia.org/wiki/Cardiac_pacing "Cardiac pacing"). Temporary pacing may be necessary for reversible causes of very slow heartbeats, or [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia") (for example, from [drug overdose](https://en.wikipedia.org/wiki/Drug_overdose "Drug overdose") or [myocardial infarction](https://en.wikipedia.org/wiki/Myocardial_infarction "Myocardial infarction")). A permanent [pacemaker](https://en.wikipedia.org/wiki/Artificial_pacemaker "Artificial pacemaker") may be placed in situations where the bradycardia is not expected to recover. ### Electrical cautery \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=25 "Edit section: Electrical cautery")\] Some cardiologists further sub-specialize into electrophysiology. In specialized [catheter laboratories](https://en.wikipedia.org/wiki/Catheter "Catheter"), they use fine probes inserted through the blood vessels to map electrical activity from within the heart. This allows abnormal areas of conduction to be located very accurately and subsequently destroyed by heat, cold, electrical, or laser probes in a process called [catheter ablation](https://en.wikipedia.org/wiki/Catheter_ablation "Catheter ablation"). This procedure may be completely curative for some forms of arrhythmia, but for others, the success rate remains disappointing. [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") is often curable by ablating one of the pathways in the [AV node](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node") (usually the slow pathway). [Atrial fibrillation](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation") can also be treated, by performing a [pulmonary vein](https://en.wikipedia.org/wiki/Pulmonary_vein "Pulmonary vein") isolation, but the results are less reliable. ## Research \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=26 "Edit section: Research")\] Arrhythmias due to medications have been reported since the 1920s with the use of [quinine](https://en.wikipedia.org/wiki/Quinine "Quinine").[\[34\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Hei2010-34) In the 1960s and 1970s problems with antihistamines and antipsychotics were discovered.[\[34\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Hei2010-34) It was not until the 1980s that the underlying issue, [QTc prolongation](https://en.wikipedia.org/wiki/QT_interval#Abnormal_intervals "QT interval") was determined.[\[34\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Hei2010-34) [Osborn waves](https://en.wikipedia.org/wiki/J_wave "J wave") on [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiography "Electrocardiography") ([ECG](https://en.wikipedia.org/wiki/ECG "ECG")) are frequent during [targeted temperature management (TTM)](https://en.wikipedia.org/wiki/Targeted_temperature_management "Targeted temperature management") after [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest"), particularly in patients treated with 33 °C.[\[35\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-:0-35) [Osborn waves](https://en.wikipedia.org/wiki/J_wave "J wave") are not associated with increased risk of [ventricular arrhythmia](https://en.wikipedia.org/wiki/Ventricular_arrhythmia "Ventricular arrhythmia"), and may be considered a [benign](https://en.wikipedia.org/wiki/Benign_early_repolarization "Benign early repolarization") physiological phenomenon, associated with lower [mortality](https://en.wikipedia.org/wiki/Mortality_rate "Mortality rate") in univariable analyses.[\[35\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-:0-35) ## See also \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=27 "Edit section: See also")\] - [Pre-excitation syndrome](https://en.wikipedia.org/wiki/Pre-excitation_syndrome "Pre-excitation syndrome") - [Holiday heart syndrome](https://en.wikipedia.org/wiki/Holiday_heart_syndrome "Holiday heart syndrome") ## References \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=28 "Edit section: References")\] 1. ^ [*a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-3) ["What Are the Signs and Symptoms of an Arrhythmia?"](https://www.nhlbi.nih.gov/health/arrhythmias/symptoms). National Heart, Lung, and Blood Institute. July 1, 2011. [Archived](https://web.archive.org/web/20150219081446/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/signs) from the original on 19 February 2015. Retrieved 7 March 2015. 2. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-3) [e](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-4) [f](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-5) [g](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-6) ["What Is Arrhythmia?"](https://web.archive.org/web/20150302074103/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/). [National Heart, Lung, and Blood Institute](https://en.wikipedia.org/wiki/National_Heart,_Lung,_and_Blood_Institute "National Heart, Lung, and Blood Institute"). July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr) on 2 March 2015. Retrieved 7 March 2015. 3. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-3) [e](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-4) [f](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-5) [g](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-6) [h](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-7) [i](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-8) ["Types of Arrhythmia"](https://web.archive.org/web/20150607165144/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/types). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/types) on 7 June 2015. Retrieved 7 March 2015. 4. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-3) ["Who Is at Risk for an Arrhythmia?"](https://web.archive.org/web/20150303190136/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/atrisk). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/atrisk) on 3 March 2015. Retrieved 7 March 2015. 5. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Diag_5-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Diag_5-1) ["How Are Arrhythmias Diagnosed?"](https://web.archive.org/web/20150218075708/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/diagnosis). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/diagnosis) on 18 February 2015. Retrieved 7 March 2015. 6. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-3) [e](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-4) [f](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-5) [g](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-6) ["How Are Arrhythmias Treated?"](https://web.archive.org/web/20150217135319/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/treatment). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/treatment) on 17 February 2015. Retrieved 7 March 2015. 7. 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[ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [0683307460](https://en.wikipedia.org/wiki/Special:BookSources/0683307460 "Special:BookSources/0683307460") . \[[page needed](https://en.wikipedia.org/wiki/Wikipedia:Citing_sources "Wikipedia:Citing sources")\] 15. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-15) Zipes DP, Wellens HJ (November 1998). ["Sudden cardiac death"](https://doi.org/10.1161%2F01.CIR.98.21.2334). Circulation. 98 (21): 2334–2351\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1161/01.CIR.98.21.2334](https://doi.org/10.1161%2F01.CIR.98.21.2334). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [9826323](https://pubmed.ncbi.nlm.nih.gov/9826323). 16. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-16) Deo R, Albert CM (January 2012). ["Epidemiology and genetics of sudden cardiac death"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399522). Circulation. 125 (4): 620–637\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1161/circulationaha.111.023838](https://doi.org/10.1161%2Fcirculationaha.111.023838). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [3399522](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3399522). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [22294707](https://pubmed.ncbi.nlm.nih.gov/22294707). 17. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-a-_Chugh-2008_17-0) Chugh SS, Reinier K, Teodorescu C, Evanado A, Kehr E, Al Samara M, et al. (2008). ["Epidemiology of sudden cardiac death: clinical and research implications"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2621010). Progress in Cardiovascular Diseases. 51 (3): 213–228\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.pcad.2008.06.003](https://doi.org/10.1016%2Fj.pcad.2008.06.003). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [2621010](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2621010). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [19026856](https://pubmed.ncbi.nlm.nih.gov/19026856). 18. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-18) Winkel BG, Holst AG, Theilade J, Kristensen IB, Thomsen JL, Ottesen GL, et al. (April 2011). ["Nationwide study of sudden cardiac death in persons aged 1-35 years"](https://doi.org/10.1093%2Feurheartj%2Fehq428). European Heart Journal. 32 (8): 983–990\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1093/eurheartj/ehq428](https://doi.org/10.1093%2Feurheartj%2Fehq428). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [21131293](https://pubmed.ncbi.nlm.nih.gov/21131293). 19. ^ [*a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-Batra_19-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-Batra_19-1) Batra AS, Balaji S (2019). ["Fetal arrhythmias: Diagnosis and management"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6531664). Indian Pacing and Electrophysiology Journal. 19* (3): 104–109\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.ipej.2019.02.007](https://doi.org/10.1016%2Fj.ipej.2019.02.007). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [6531664](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6531664). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [30817991](https://pubmed.ncbi.nlm.nih.gov/30817991). 20. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-20) ["Passing Out (Syncope) Caused by Arrhythmias"](https://www.cardiosmart.org/healthwise/te71/52ab/c/te7152abc). Retrieved 13 April 2020. 21. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-Antzelevitch_2011_21-0) Antzelevitch C, Burashnikov A (March 2011). ["Overview of Basic Mechanisms of Cardiac Arrhythmia"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164530). Cardiac Electrophysiology Clinics. 3 (1): 23–45\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.ccep.2010.10.012](https://doi.org/10.1016%2Fj.ccep.2010.10.012). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [3164530](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3164530). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [21892379](https://pubmed.ncbi.nlm.nih.gov/21892379). 22. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-22) Willcox ME, Compton SJ, Bardy GH (2021-12-01). ["Continuous ECG monitoring versus mobile telemetry: A comparison of arrhythmia diagnostics in human- versus algorithmic-dependent systems"](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703156). Heart Rhythm O2. 2 (6, Part A): 543–559\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.hroo.2021.09.008](https://doi.org/10.1016%2Fj.hroo.2021.09.008). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [2666-5018](https://search.worldcat.org/issn/2666-5018). [PMC](https://en.wikipedia.org/wiki/PMC_\(identifier\) "PMC (identifier)") [8703156](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8703156). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [34988499](https://pubmed.ncbi.nlm.nih.gov/34988499). 23. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-23) Kiladze MR, Lyakhova UA, Lyakhov PA, Nagornov NN, Vahabi M (2023). ["Multimodal Neural Network for Recognition of Cardiac Arrhythmias Based on 12-Load Electrocardiogram Signals"](https://doi.org/10.1109%2FACCESS.2023.3335176). IEEE Access. 11: 133744–133754\. [Bibcode](https://en.wikipedia.org/wiki/Bibcode_\(identifier\) "Bibcode (identifier)"):[2023IEEEA..11m3744K](https://ui.adsabs.harvard.edu/abs/2023IEEEA..11m3744K). [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1109/ACCESS.2023.3335176](https://doi.org/10.1109%2FACCESS.2023.3335176). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [2169-3536](https://search.worldcat.org/issn/2169-3536). 24. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-MeigasKaik2008_24-0) Anier A, Kaik J, Meigas K (2008). "Device and methods for performing transesophageal stimulation at reduced pacing current threshold". Estonian Journal of Engineering. 57 (2): 154. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.3176/eng.2008.2.05](https://doi.org/10.3176%2Feng.2008.2.05). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [42055085](https://api.semanticscholar.org/CorpusID:42055085). 25. ^ [*a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-PehrsonBlomstr%C3%B6-LUNDQVIST1994_25-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-PehrsonBlomstr%C3%B6-LUNDQVIST1994_25-1) Pehrson SM, Blomström-Lundqvist C, Ljungström E, Blomström P (October 1994). ["Clinical value of transesophageal atrial stimulation and recording in patients with arrhythmia-related symptoms or documented supraventricular tachycardia--correlation to clinical history and invasive studies"](https://doi.org/10.1002%2Fclc.4960171004). Clinical Cardiology. 17* (10): 528–534\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1002/clc.4960171004](https://doi.org/10.1002%2Fclc.4960171004). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [8001299](https://pubmed.ncbi.nlm.nih.gov/8001299). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [7097362](https://api.semanticscholar.org/CorpusID:7097362). 26. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-26) Yasuma F, Hayano J (February 2004). "Respiratory sinus arrhythmia: why does the heartbeat synchronize with respiratory rhythm?". Chest. 125 (2): 683–690\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1378/chest.125.2.683](https://doi.org/10.1378%2Fchest.125.2.683). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [14769752](https://pubmed.ncbi.nlm.nih.gov/14769752). 27. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-27) Peressutti C, Martín-González JM, M García-Manso J, Mesa D (November 2010). "Heart rate dynamics in different levels of Zen meditation". International Journal of Cardiology. 145 (1): 142–146\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.ijcard.2009.06.058](https://doi.org/10.1016%2Fj.ijcard.2009.06.058). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [19631997](https://pubmed.ncbi.nlm.nih.gov/19631997). 28. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-a-_Wiener-1946_28-0) Wiener N, Rosenblueth A (July 1946). "The mathematical formulation of the problem of conduction of impulses in a network of connected excitable elements, specifically in cardiac muscle". Archivos del Instituto de Cardiologia de Mexico. 16 (3): 205–265\. [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [20245817](https://pubmed.ncbi.nlm.nih.gov/20245817). 29. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-a-_Allessie-1976_29-0) [Allessie MA](https://en.wikipedia.org/wiki/Maurits_Allessie "Maurits Allessie"), Bonke FI, Schopman FJ (August 1976). ["Circus movement in rabbit atrial muscle as a mechanism of tachycardia. II. The role of nonuniform recovery of excitability in the occurrence of unidirectional block, as studied with multiple microelectrodes"](https://doi.org/10.1161%2F01.RES.39.2.168). Circulation Research. 39 (2): 168–177\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1161/01.RES.39.2.168](https://doi.org/10.1161%2F01.RES.39.2.168). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [939001](https://pubmed.ncbi.nlm.nih.gov/939001). 30. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-b-Mandel-1995_30-0) Mandel WJ, ed. (1995). Cardiac Arrhythmias: Their Mechanisms, Diagnosis, and Management (3 ed.). Lippincott Williams & Wilkins. [ISBN](https://en.wikipedia.org/wiki/ISBN_\(identifier\) "ISBN (identifier)") [978-0-397-51185-3](https://en.wikipedia.org/wiki/Special:BookSources/978-0-397-51185-3 "Special:BookSources/978-0-397-51185-3") . \[[page needed](https://en.wikipedia.org/wiki/Wikipedia:Citing_sources "Wikipedia:Citing sources")\] 31. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-a-_Coronel-2007_31-0) Den Ruijter HM, Berecki G, Opthof T, Verkerk AO, Zock PL, Coronel R (January 2007). ["Pro- and antiarrhythmic properties of a diet rich in fish oil"](https://doi.org/10.1016%2Fj.cardiores.2006.06.014). Cardiovascular Research. 73 (2): 316–325\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.cardiores.2006.06.014](https://doi.org/10.1016%2Fj.cardiores.2006.06.014). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [16859661](https://pubmed.ncbi.nlm.nih.gov/16859661). 32. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-32) Barrett ML, Smith MW, Elizhauser A, Honigman LS, Pines JM (December 2014). ["Utilization of Intensive Care Services, 2011"](https://www.hcup-us.ahrq.gov/reports/statbriefs/sb185-Hospital-Intensive-Care-Units-2011.jsp). HCUP Statistical Brief (185). Rockville, MD: Agency for Healthcare Research and Quality. [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [25654157](https://pubmed.ncbi.nlm.nih.gov/25654157). [Archived](https://web.archive.org/web/20150402162800/https://www.hcup-us.ahrq.gov/reports/statbriefs/sb185-Hospital-Intensive-Care-Units-2011.jsp) from the original on 2015-04-02. 33. [^](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-33) ["AED Buyer's Guide \\| AED Prices & Comparison"](https://www.aedbrands.com/aed-buyers-guide/). AED Brands. Retrieved 2021-08-13. 34. ^ [*a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-Hei2010_34-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-Hei2010_34-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-Hei2010_34-2) Heist EK, Ruskin JN (October 2010). ["Drug-induced arrhythmia"](https://doi.org/10.1161%2Fcirculationaha.109.894725). Circulation. 122* (14): 1426–1435\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1161/circulationaha.109.894725](https://doi.org/10.1161%2Fcirculationaha.109.894725). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [20921449](https://pubmed.ncbi.nlm.nih.gov/20921449). 35. ^ [*a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-:0_35-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-:0_35-1) Hadziselimovic E, Thomsen JH, Kjaergaard J, Køber L, Graff C, Pehrson S, et al. (July 2018). ["Osborn waves following out-of-hospital cardiac arrest—Effect of level of temperature management and risk of arrhythmia and death"](https://doi.org/10.1016/j.resuscitation.2018.04.037). Resuscitation. 128: 119–125\. [doi](https://en.wikipedia.org/wiki/Doi_\(identifier\) "Doi (identifier)"):[10\.1016/j.resuscitation.2018.04.037](https://doi.org/10.1016%2Fj.resuscitation.2018.04.037). [ISSN](https://en.wikipedia.org/wiki/ISSN_\(identifier\) "ISSN (identifier)") [0300-9572](https://search.worldcat.org/issn/0300-9572). [PMID](https://en.wikipedia.org/wiki/PMID_\(identifier\) "PMID (identifier)") [29723608](https://pubmed.ncbi.nlm.nih.gov/29723608). [S2CID](https://en.wikipedia.org/wiki/S2CID_\(identifier\) "S2CID (identifier)") [19236851](https://api.semanticscholar.org/CorpusID:19236851). ## External links \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=29 "Edit section: External links")\] \| \| \| \|---\|---\| \| Classification \| [D](https://www.wikidata.org/wiki/Q189331 "d:Q189331") [ICD](https://en.wikipedia.org/wiki/International_Statistical_Classification_of_Diseases_and_Related_Health_Problems "International Statistical Classification of Diseases and Related Health Problems")\-[10](https://en.wikipedia.org/wiki/ICD-10 "ICD-10"): [I47](https://icd.who.int/browse10/2019/en#/I47) – [I49](https://icd.who.int/browse10/2019/en#/I49) [ICD](https://en.wikipedia.org/wiki/International_Statistical_Classification_of_Diseases_and_Related_Health_Problems "International Statistical Classification of Diseases and Related Health Problems")\-[9-CM](https://en.wikipedia.org/wiki/List_of_ICD-9_codes "List of ICD-9 codes"): [427](http://www.icd9data.com/getICD9Code.ashx?icd9=427) [MeSH](https://en.wikipedia.org/wiki/Medical_Subject_Headings "Medical Subject Headings"): [D001145](https://meshb.nlm.nih.gov/record/ui?ui=D001145) [DiseasesDB](https://en.wikipedia.org/wiki/Diseases_Database "Diseases Database"): [15206](http://www.diseasesdatabase.com/ddb15206.htm) \| \| External resources \| [MedlinePlus](https://en.wikipedia.org/wiki/MedlinePlus "MedlinePlus"): [001101](https://www.nlm.nih.gov/medlineplus/ency/article/001101.htm) \| \| [v](https://en.wikipedia.org/wiki/Template:Heart_diseases "Template:Heart diseases") [t](https://en.wikipedia.org/wiki/Template_talk:Heart_diseases "Template talk:Heart diseases") [e](https://en.wikipedia.org/wiki/Special:EditPage/Template:Heart_diseases "Special:EditPage/Template:Heart diseases")[Cardiovascular disease](https://en.wikipedia.org/wiki/Cardiovascular_disease "Cardiovascular disease") (heart) \| \| \|---\|---\| \| [Ischemia](https://en.wikipedia.org/wiki/Ischemia "Ischemia") \| \| \| \| \| \| Coronary disease \| [Coronary artery disease](https://en.wikipedia.org/wiki/Coronary_artery_disease "Coronary artery disease") (CAD) [Coronary artery aneurysm](https://en.wikipedia.org/wiki/Coronary_artery_aneurysm "Coronary artery aneurysm") [Spontaneous coronary artery dissection](https://en.wikipedia.org/wiki/Spontaneous_coronary_artery_dissection "Spontaneous coronary artery dissection") (SCAD) [Coronary thrombosis](https://en.wikipedia.org/wiki/Coronary_thrombosis "Coronary thrombosis") [Coronary vasospasm](https://en.wikipedia.org/wiki/Coronary_vasospasm "Coronary vasospasm") [Myocardial bridge](https://en.wikipedia.org/wiki/Myocardial_bridge "Myocardial bridge") \| \| Active ischemia \| [Angina pectoris](https://en.wikipedia.org/wiki/Angina "Angina") [Prinzmetal's angina](https://en.wikipedia.org/wiki/Prinzmetal%27s_angina "Prinzmetal's angina") [Stable angina](https://en.wikipedia.org/wiki/Stable_angina "Stable angina") [Acute coronary syndrome](https://en.wikipedia.org/wiki/Acute_coronary_syndrome "Acute coronary syndrome") [Myocardial infarction](https://en.wikipedia.org/wiki/Myocardial_infarction "Myocardial infarction") [Unstable angina](https://en.wikipedia.org/wiki/Unstable_angina "Unstable angina") \| \| [Sequelae](https://en.wikipedia.org/wiki/Myocardial_infarction_complications "Myocardial infarction complications") \| hours* [Hibernating myocardium](https://en.wikipedia.org/wiki/Hibernating_myocardium "Hibernating myocardium") [Myocardial stunning](https://en.wikipedia.org/wiki/Myocardial_stunning "Myocardial stunning") days [Myocardial rupture](https://en.wikipedia.org/wiki/Myocardial_rupture "Myocardial rupture") weeks [Ventricular aneurysm](https://en.wikipedia.org/wiki/Ventricular_aneurysm "Ventricular aneurysm") [Dressler syndrome](https://en.wikipedia.org/wiki/Dressler_syndrome "Dressler syndrome") \| \| Layers \| \| \| \| \| \| [Pericardium](https://en.wikipedia.org/wiki/Pericardium "Pericardium") \| [Pericarditis](https://en.wikipedia.org/wiki/Pericarditis "Pericarditis") [Acute](https://en.wikipedia.org/wiki/Acute_pericarditis "Acute pericarditis") [Chronic](https://en.wikipedia.org/wiki/Pericarditis#Acute_vs._chronic "Pericarditis") / [Constrictive](https://en.wikipedia.org/wiki/Constrictive_pericarditis "Constrictive pericarditis") [Pericardial effusion](https://en.wikipedia.org/wiki/Pericardial_effusion "Pericardial effusion") [Cardiac tamponade](https://en.wikipedia.org/wiki/Cardiac_tamponade "Cardiac tamponade") [Hemopericardium](https://en.wikipedia.org/wiki/Hemopericardium "Hemopericardium") \| \| [Myocardium](https://en.wikipedia.org/wiki/Cardiac_muscle "Cardiac muscle") \| [Myocarditis](https://en.wikipedia.org/wiki/Myocarditis "Myocarditis") [Chagas disease](https://en.wikipedia.org/wiki/Chagas_disease "Chagas disease") [Cardiomyopathy](https://en.wikipedia.org/wiki/Cardiomyopathy "Cardiomyopathy") [Dilated](https://en.wikipedia.org/wiki/Dilated_cardiomyopathy "Dilated cardiomyopathy") [Alcoholic](https://en.wikipedia.org/wiki/Alcoholic_cardiomyopathy "Alcoholic cardiomyopathy") [Hypertrophic](https://en.wikipedia.org/wiki/Hypertrophic_cardiomyopathy "Hypertrophic cardiomyopathy") [Tachycardia-induced](https://en.wikipedia.org/wiki/Tachycardia-induced_cardiomyopathy "Tachycardia-induced cardiomyopathy") [Restrictive](https://en.wikipedia.org/wiki/Restrictive_cardiomyopathy "Restrictive cardiomyopathy") [Loeffler endocarditis](https://en.wikipedia.org/wiki/Loeffler_endocarditis "Loeffler endocarditis") [Cardiac amyloidosis](https://en.wikipedia.org/wiki/Amyloidosis "Amyloidosis") [Endocardial fibroelastosis](https://en.wikipedia.org/wiki/Endocardial_fibroelastosis "Endocardial fibroelastosis") [Viral](https://en.wikipedia.org/wiki/Viral_cardiomyopathy "Viral cardiomyopathy") [Arrhythmogenic right ventricular dysplasia](https://en.wikipedia.org/wiki/Arrhythmogenic_right_ventricular_dysplasia "Arrhythmogenic right ventricular dysplasia") \| \| [Endocardium](https://en.wikipedia.org/wiki/Endocardium "Endocardium") / [valves](https://en.wikipedia.org/wiki/Valvular_heart_disease "Valvular heart disease") \| \| \| \| \| \| [Endocarditis](https://en.wikipedia.org/wiki/Endocarditis "Endocarditis") \| [infective endocarditis](https://en.wikipedia.org/wiki/Infective_endocarditis "Infective endocarditis") [Subacute bacterial endocarditis](https://en.wikipedia.org/wiki/Subacute_bacterial_endocarditis "Subacute bacterial endocarditis") [non-infective endocarditis](https://en.wikipedia.org/wiki/Endocarditis#Non-infective_endocarditis "Endocarditis") [Libman–Sacks endocarditis](https://en.wikipedia.org/wiki/Libman%E2%80%93Sacks_endocarditis "Libman–Sacks endocarditis") [Nonbacterial thrombotic endocarditis](https://en.wikipedia.org/wiki/Nonbacterial_thrombotic_endocarditis "Nonbacterial thrombotic endocarditis") \| \| Valves \| [mitral](https://en.wikipedia.org/wiki/Mitral_valve "Mitral valve") [prolapse](https://en.wikipedia.org/wiki/Mitral_valve_prolapse "Mitral valve prolapse") [stenosis](https://en.wikipedia.org/wiki/Mitral_valve_stenosis "Mitral valve stenosis") [regurgitation](https://en.wikipedia.org/wiki/Mitral_regurgitation "Mitral regurgitation") [aortic](https://en.wikipedia.org/wiki/Aortic_valve "Aortic valve") [stenosis](https://en.wikipedia.org/wiki/Aortic_stenosis "Aortic stenosis") [regurgitation](https://en.wikipedia.org/wiki/Aortic_regurgitation "Aortic regurgitation") [tricuspid](https://en.wikipedia.org/wiki/Tricuspid_valve "Tricuspid valve") [stenosis](https://en.wikipedia.org/wiki/Tricuspid_valve_stenosis "Tricuspid valve stenosis") [regurgitation](https://en.wikipedia.org/wiki/Tricuspid_regurgitation "Tricuspid regurgitation") [pulmonary](https://en.wikipedia.org/wiki/Pulmonary_valve "Pulmonary valve") [stenosis](https://en.wikipedia.org/wiki/Pulmonary_valve_stenosis "Pulmonary valve stenosis") [regurgitation](https://en.wikipedia.org/wiki/Pulmonary_regurgitation "Pulmonary regurgitation") \| \| [Conduction](https://en.wikipedia.org/wiki/Cardiac_conduction_system "Cardiac conduction system") / [arrhythmia]() \| \| \| \| \| \| [Bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia") \| [Sinus bradycardia](https://en.wikipedia.org/wiki/Sinus_bradycardia "Sinus bradycardia") [Sick sinus syndrome](https://en.wikipedia.org/wiki/Sick_sinus_syndrome "Sick sinus syndrome") [Heart block](https://en.wikipedia.org/wiki/Heart_block "Heart block"): [Sinoatrial](https://en.wikipedia.org/wiki/Sinoatrial_block "Sinoatrial block") [AV](https://en.wikipedia.org/wiki/Atrioventricular_block "Atrioventricular block") [1°](https://en.wikipedia.org/wiki/First-degree_atrioventricular_block "First-degree atrioventricular block") [2°](https://en.wikipedia.org/wiki/Second-degree_atrioventricular_block "Second-degree atrioventricular block") [3°](https://en.wikipedia.org/wiki/Third-degree_atrioventricular_block "Third-degree atrioventricular block") [Intraventricular](https://en.wikipedia.org/wiki/Intraventricular_block "Intraventricular block") [Bundle branch block](https://en.wikipedia.org/wiki/Bundle_branch_block "Bundle branch block") [Right](https://en.wikipedia.org/wiki/Right_bundle_branch_block "Right bundle branch block") [Left](https://en.wikipedia.org/wiki/Left_bundle_branch_block "Left bundle branch block") [Left anterior fascicle](https://en.wikipedia.org/wiki/Left_anterior_fascicular_block "Left anterior fascicular block") [Left posterior fascicle](https://en.wikipedia.org/wiki/Left_posterior_fascicular_block "Left posterior fascicular block") [Bifascicular](https://en.wikipedia.org/wiki/Bifascicular_block "Bifascicular block") [Trifascicular](https://en.wikipedia.org/wiki/Trifascicular_block "Trifascicular block") [Adams–Stokes syndrome](https://en.wikipedia.org/wiki/Adams%E2%80%93Stokes_syndrome "Adams–Stokes syndrome") \| \| [Tachycardia](https://en.wikipedia.org/wiki/Tachycardia "Tachycardia") ([paroxysmal](https://en.wikipedia.org/wiki/Paroxysmal_tachycardia "Paroxysmal tachycardia") and [sinus](https://en.wikipedia.org/wiki/Sinus_tachycardia "Sinus tachycardia")) \| \| \| \| \| \| [Supraventricular](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia") \| [Atrial](https://en.wikipedia.org/wiki/Atrial_tachycardia "Atrial tachycardia") [Multifocal](https://en.wikipedia.org/wiki/Multifocal_atrial_tachycardia "Multifocal atrial tachycardia") [Junctional](https://en.wikipedia.org/wiki/Junctional_tachycardia "Junctional tachycardia") [AV nodal reentrant](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") [Junctional ectopic](https://en.wikipedia.org/wiki/Junctional_ectopic_tachycardia "Junctional ectopic tachycardia") \| \| [Ventricular](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia") \| [Accelerated idioventricular rhythm](https://en.wikipedia.org/wiki/Accelerated_idioventricular_rhythm "Accelerated idioventricular rhythm") [Catecholaminergic polymorphic](https://en.wikipedia.org/wiki/Catecholaminergic_polymorphic_ventricular_tachycardia "Catecholaminergic polymorphic ventricular tachycardia") [Torsades de pointes](https://en.wikipedia.org/wiki/Torsades_de_pointes "Torsades de pointes") \| \| Premature contraction \| [Atrial](https://en.wikipedia.org/wiki/Premature_atrial_contraction "Premature atrial contraction") [Junctional](https://en.wikipedia.org/wiki/Premature_junctional_contraction "Premature junctional contraction") [Ventricular](https://en.wikipedia.org/wiki/Premature_ventricular_contraction "Premature ventricular contraction") \| \| [Pre-excitation syndrome](https://en.wikipedia.org/wiki/Pre-excitation_syndrome "Pre-excitation syndrome") \| [Lown–Ganong–Levine](https://en.wikipedia.org/wiki/Lown%E2%80%93Ganong%E2%80%93Levine_syndrome "Lown–Ganong–Levine syndrome") [Wolff–Parkinson–White](https://en.wikipedia.org/wiki/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome "Wolff–Parkinson–White syndrome") \| \| Flutter / [fibrillation](https://en.wikipedia.org/wiki/Fibrillation "Fibrillation") \| [Atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter") [Ventricular flutter](https://en.wikipedia.org/wiki/Ventricular_flutter "Ventricular flutter") [Atrial fibrillation](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation") [Familial](https://en.wikipedia.org/wiki/Familial_atrial_fibrillation "Familial atrial fibrillation") [Ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") \| \| [Pacemaker](https://en.wikipedia.org/wiki/Artificial_cardiac_pacemaker "Artificial cardiac pacemaker") \| [Ectopic pacemaker](https://en.wikipedia.org/wiki/Ectopic_pacemaker "Ectopic pacemaker") / [Ectopic beat](https://en.wikipedia.org/wiki/Ectopic_beat "Ectopic beat") [Multifocal atrial tachycardia](https://en.wikipedia.org/wiki/Multifocal_atrial_tachycardia "Multifocal atrial tachycardia") [Pacemaker syndrome](https://en.wikipedia.org/wiki/Pacemaker_syndrome "Pacemaker syndrome") [Parasystole](https://en.wikipedia.org/wiki/Parasystole "Parasystole") [Wandering atrial pacemaker](https://en.wikipedia.org/wiki/Wandering_atrial_pacemaker "Wandering atrial pacemaker") \| \| [Long QT syndrome](https://en.wikipedia.org/wiki/Long_QT_syndrome "Long QT syndrome") \| [Andersen–Tawil](https://en.wikipedia.org/wiki/Andersen%E2%80%93Tawil_syndrome "Andersen–Tawil syndrome") [Jervell and Lange-Nielsen](https://en.wikipedia.org/wiki/Jervell_and_Lange-Nielsen_syndrome "Jervell and Lange-Nielsen syndrome") [Romano–Ward](https://en.wikipedia.org/wiki/Romano%E2%80%93Ward_syndrome "Romano–Ward syndrome") \| \| [Cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest") \| [Sudden cardiac death](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest") [Asystole](https://en.wikipedia.org/wiki/Asystole "Asystole") [Pulseless electrical activity](https://en.wikipedia.org/wiki/Pulseless_electrical_activity "Pulseless electrical activity") [Sinoatrial arrest](https://en.wikipedia.org/wiki/Sinoatrial_arrest "Sinoatrial arrest") \| \| Other / ungrouped \| [hexaxial reference system](https://en.wikipedia.org/wiki/Hexaxial_reference_system "Hexaxial reference system") [Right axis deviation](https://en.wikipedia.org/wiki/Right_axis_deviation "Right axis deviation") [Left axis deviation](https://en.wikipedia.org/wiki/Left_axis_deviation "Left axis deviation") [QT](https://en.wikipedia.org/wiki/QT_interval "QT interval") [Short QT syndrome](https://en.wikipedia.org/wiki/Short_QT_syndrome "Short QT syndrome") [T](https://en.wikipedia.org/wiki/T_wave "T wave") [T wave alternans](https://en.wikipedia.org/wiki/T_wave_alternans "T wave alternans") [ST](https://en.wikipedia.org/wiki/ST_segment "ST segment") [J wave](https://en.wikipedia.org/wiki/J_wave "J wave") [ST elevation](https://en.wikipedia.org/wiki/ST_elevation "ST elevation") [ST depression](https://en.wikipedia.org/wiki/ST_depression "ST depression") [Strain pattern](https://en.wikipedia.org/wiki/Strain_pattern "Strain pattern") \| \| [Cardiomegaly](https://en.wikipedia.org/wiki/Cardiomegaly "Cardiomegaly") \| [Ventricular hypertrophy](https://en.wikipedia.org/wiki/Ventricular_hypertrophy "Ventricular hypertrophy") [Left](https://en.wikipedia.org/wiki/Left_ventricular_hypertrophy "Left ventricular hypertrophy") [Right](https://en.wikipedia.org/wiki/Right_ventricular_hypertrophy "Right ventricular hypertrophy") [Pulmonary](https://en.wikipedia.org/wiki/Pulmonary_heart_disease "Pulmonary heart disease") [Atrial enlargement](https://en.wikipedia.org/wiki/Atrial_enlargement "Atrial enlargement") [Left](https://en.wikipedia.org/wiki/Left_atrial_enlargement "Left atrial enlargement") [Right](https://en.wikipedia.org/wiki/Right_atrial_enlargement "Right atrial enlargement") [Athletic heart syndrome](https://en.wikipedia.org/wiki/Athletic_heart_syndrome "Athletic heart syndrome") \| \| Other \| [Cardiac fibrosis](https://en.wikipedia.org/wiki/Cardiac_fibrosis "Cardiac fibrosis") [Heart failure](https://en.wikipedia.org/wiki/Heart_failure "Heart failure") [Diastolic heart failure](https://en.wikipedia.org/wiki/Diastolic_heart_failure "Diastolic heart failure") [Cardiac asthma](https://en.wikipedia.org/wiki/Cardiac_asthma "Cardiac asthma") [Rheumatic fever](https://en.wikipedia.org/wiki/Rheumatic_fever "Rheumatic fever") [Obstructive shock](https://en.wikipedia.org/wiki/Obstructive_shock "Obstructive shock") \| \| [Authority control databases](https://en.wikipedia.org/wiki/Help:Authority_control "Help:Authority control") [![Edit this at 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Readable Markdown	\| Arrhythmia \| \| \|---\|---\| \| Other names \| Cardiac arrhythmia, heart arrhythmia, dysrhythmia, irregular heartbeat \| \| [![](https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/Ventricular_fibrillation.png/330px-Ventricular_fibrillation.png)](https://en.wikipedia.org/wiki/File:Ventricular_fibrillation.png) \| \| \| [Ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") (VF) showing disorganized electrical activity producing a spiked tracing on an [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") (ECG) \| \| \| [Specialty](https://en.wikipedia.org/wiki/Medical_specialty "Medical specialty") \| [Cardiology](https://en.wikipedia.org/wiki/Cardiology "Cardiology") \| \| [Symptoms](https://en.wikipedia.org/wiki/Signs_and_symptoms "Signs and symptoms") \| [Palpitations](https://en.wikipedia.org/wiki/Palpitations "Palpitations"), [dizziness](https://en.wikipedia.org/wiki/Dizziness "Dizziness") or [lightheadedness](https://en.wikipedia.org/wiki/Presyncope "Presyncope"), [passing out](https://en.wikipedia.org/wiki/Syncope_\(medicine\) "Syncope (medicine)"), [shortness of breath](https://en.wikipedia.org/wiki/Shortness_of_breath "Shortness of breath"), [chest pain](https://en.wikipedia.org/wiki/Chest_pain "Chest pain"),[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) [decreased level of consciousness](https://en.wikipedia.org/wiki/Decreased_level_of_consciousness "Decreased level of consciousness") \| \| [Complications](https://en.wikipedia.org/wiki/Complication_\(medicine\) "Complication (medicine)") \| [Stroke](https://en.wikipedia.org/wiki/Stroke "Stroke"), [heart failure](https://en.wikipedia.org/wiki/Heart_failure "Heart failure")[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2)[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3), [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest") \| \| Usual onset \| Older age[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) \| \| Types \| [Extra beats](https://en.wikipedia.org/wiki/Premature_heart_beat "Premature heart beat"), [supraventricular tachycardias](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia"), [ventricular arrhythmias](https://en.wikipedia.org/wiki/Ventricular_arrhythmia "Ventricular arrhythmia"), [bradyarrhythmias](https://en.wikipedia.org/wiki/Bradyarrhythmia "Bradyarrhythmia")[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) \| \| [Causes](https://en.wikipedia.org/wiki/Cause_\(medicine\) "Cause (medicine)") \| Problems with the [electrical conduction system of the heart](https://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart "Electrical conduction system of the heart")[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) \| \| [Diagnostic method](https://en.wikipedia.org/wiki/Medical_diagnosis "Medical diagnosis") \| [Electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram"), [Holter monitor](https://en.wikipedia.org/wiki/Holter_monitor "Holter monitor")[\[5\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Diag-5) \| \| Treatment \| Medications, medical procedures ([pacemaker](https://en.wikipedia.org/wiki/Pacemaker "Pacemaker")), surgery[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) \| \| Frequency \| Millions[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) \| ![](https://upload.wikimedia.org/wikipedia/commons/thumb/8/87/Gnome-mime-sound-openclipart.svg/60px-Gnome-mime-sound-openclipart.svg.png) Heart sounds of a girl experiencing arrhythmia after exercising. Arrhythmias, also known as cardiac arrhythmias, are irregularities in the [heartbeat](https://en.wikipedia.org/wiki/Cardiac_cycle "Cardiac cycle"), including when it is too fast or too slow.[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) Essentially, this is anything but [normal sinus rhythm](https://en.wikipedia.org/wiki/Normal_sinus_rhythm "Normal sinus rhythm"). A resting [heart rate](https://en.wikipedia.org/wiki/Heart_rate "Heart rate") that is too fast – above 100 beats per minute in adults – is called [tachycardia](https://en.wikipedia.org/wiki/Tachycardia "Tachycardia"), and a resting heart rate that is too slow – below 60 beats per minute – is called [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia").[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) Some types of arrhythmias have no [symptoms](https://en.wikipedia.org/wiki/Symptoms "Symptoms").[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) Symptoms, when present, may include [palpitations](https://en.wikipedia.org/wiki/Palpitations "Palpitations") or feeling a pause between heartbeats.[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) In more serious cases, there may be [lightheadedness](https://en.wikipedia.org/wiki/Presyncope "Presyncope"), [passing out](https://en.wikipedia.org/wiki/Syncope_\(medicine\) "Syncope (medicine)"), [shortness of breath](https://en.wikipedia.org/wiki/Shortness_of_breath "Shortness of breath"), [chest pain](https://en.wikipedia.org/wiki/Chest_pain "Chest pain"), or [decreased level of consciousness](https://en.wikipedia.org/wiki/Decreased_level_of_consciousness "Decreased level of consciousness").[\[1\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Sym-1) While most cases of arrhythmia are not serious, some predispose a person to complications such as [stroke](https://en.wikipedia.org/wiki/Stroke "Stroke") or [heart failure](https://en.wikipedia.org/wiki/Heart_failure "Heart failure").[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2)[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Others may result in [sudden death](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Arrhythmias are often categorized into four groups: [extra beats](https://en.wikipedia.org/wiki/Premature_heart_beat "Premature heart beat"), [supraventricular tachycardias](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia"), [ventricular arrhythmias](https://en.wikipedia.org/wiki/Ventricular_arrhythmia "Ventricular arrhythmia") and [bradyarrhythmias](https://en.wikipedia.org/wiki/Bradyarrhythmia "Bradyarrhythmia").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Extra beats include [premature atrial contractions](https://en.wikipedia.org/wiki/Premature_atrial_contraction "Premature atrial contraction"), [premature ventricular contractions](https://en.wikipedia.org/wiki/Premature_ventricular_contraction "Premature ventricular contraction") and [premature junctional contractions](https://en.wikipedia.org/wiki/Premature_junctional_contractions "Premature junctional contractions").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Supraventricular tachycardias include [atrial fibrillation](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation"), [atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter") and [paroxysmal supraventricular tachycardia](https://en.wikipedia.org/wiki/Paroxysmal_supraventricular_tachycardia "Paroxysmal supraventricular tachycardia").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) Ventricular arrhythmias include [ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") and [ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia").[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3)[\[7\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Martin2012-7) Bradyarrhythmias are due to [sinus node dysfunction](https://en.wikipedia.org/wiki/Sinus_node_dysfunction "Sinus node dysfunction") or [atrioventricular conduction disturbances](https://en.wikipedia.org/wiki/Atrioventricular_block "Atrioventricular block").[\[8\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-8) Arrhythmias are due to problems with the [electrical conduction system of the heart](https://en.wikipedia.org/wiki/Electrical_conduction_system_of_the_heart "Electrical conduction system of the heart").[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) A number of tests can help with diagnosis, including an [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") (ECG) and [Holter monitor](https://en.wikipedia.org/wiki/Holter_monitor "Holter monitor").[\[5\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Diag-5) Many arrhythmias can be effectively treated.[\[2\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Def-2) Treatments may include medications, medical procedures such as inserting a [pacemaker](https://en.wikipedia.org/wiki/Pacemaker "Pacemaker"), and surgery.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Medications for a fast heart rate may include [beta blockers](https://en.wikipedia.org/wiki/Beta_blockers "Beta blockers"), or [antiarrhythmic agents](https://en.wikipedia.org/wiki/Antiarrhythmic_agent "Antiarrhythmic agent") such as [procainamide](https://en.wikipedia.org/wiki/Procainamide "Procainamide"), which attempt to restore a normal heart rhythm.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) This latter group may have more significant side effects, especially if taken for a long period of time.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Pacemakers are often used for slow heart rates.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Those with an irregular heartbeat are often treated with [blood thinners](https://en.wikipedia.org/wiki/Blood_thinner "Blood thinner") to reduce the risk of complications.[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Those who have severe symptoms from an arrhythmia or are medically unstable may receive urgent treatment with a [controlled electric shock](https://en.wikipedia.org/wiki/Electric_shock#Medical_uses "Electric shock") in the form of [cardioversion](https://en.wikipedia.org/wiki/Cardioversion "Cardioversion") or [defibrillation](https://en.wikipedia.org/wiki/Defibrillation "Defibrillation").[\[6\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Tx-6) Arrhythmia affects millions of people.[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) In Europe and North America, as of 2014, atrial fibrillation affects about 2% to 3% of the population.[\[9\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Zoni2014-9) Atrial fibrillation and atrial flutter resulted in 112,000 deaths in 2013, up from 29,000 in 1990.[\[10\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-GDB2013-10) However, in most recent cases concerning the SARS-CoV‑2 pandemic, cardiac arrhythmias are commonly developed and associated with high morbidity and mortality among patients hospitalized with the COVID-19 infection, due to the infection's ability to cause myocardial injury.[\[11\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-11) [Sudden cardiac death](https://en.wikipedia.org/wiki/Sudden_cardiac_death "Sudden cardiac death") is the cause of about half of deaths due to [cardiovascular disease](https://en.wikipedia.org/wiki/Cardiovascular_disease "Cardiovascular disease") and about 15% of all deaths globally.[\[12\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Meh2007-12) About 80% of sudden cardiac death is the result of ventricular arrhythmias.[\[12\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Meh2007-12) Arrhythmias may occur at any age but are more common among older people.[\[4\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Risk-4) Arrhythmias may also occur in children; however, the normal range for the heart rate varies with age.[\[3\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-NIH2011Type-3) [![](https://upload.wikimedia.org/wikipedia/commons/thumb/7/77/De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png/500px-De-Atrial_ventricular_%28CardioNetworks_ECGpedia%29.png)](https://en.wikipedia.org/wiki/File:De-Atrial_ventricular_\(CardioNetworks_ECGpedia\).png) Broad classification of arrhythmias according to region of heart required to sustain the rhythm Arrhythmia may be classified by rate ([tachycardia](https://en.wikipedia.org/wiki/Tachycardia "Tachycardia"), [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia")), mechanism (automaticity, re-entry, triggered) or duration (isolated [premature beats](https://en.wikipedia.org/wiki/Premature_heart_beat "Premature heart beat"); couplets; runs, that is 3 or more beats; non-sustained = less than 30 seconds or sustained = over 30 seconds).\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Arrhythmias are also classified by site of origin:\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] - [Sinus bradycardia](https://en.wikipedia.org/wiki/Sinus_bradycardia "Sinus bradycardia") - [Sinus arrhythmia](https://en.wikipedia.org/wiki/Sinus_arrhythmia "Sinus arrhythmia") - [Sinus tachycardia](https://en.wikipedia.org/wiki/Sinus_tachycardia "Sinus tachycardia") - [Premature atrial contractions (PACs)](https://en.wikipedia.org/wiki/Premature_atrial_contraction "Premature atrial contraction") - [Wandering atrial pacemaker](https://en.wikipedia.org/wiki/Wandering_pacemaker "Wandering pacemaker") - [Atrial tachycardia](https://en.wikipedia.org/wiki/Atrial_tachycardia "Atrial tachycardia") - [Multifocal atrial tachycardia](https://en.wikipedia.org/wiki/Multifocal_atrial_tachycardia "Multifocal atrial tachycardia") - [Supraventricular tachycardia (SVT)](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia") - [Atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter") - [Atrial fibrillation (Afib)](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation") - [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") ### Junctional arrhythmia \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=3 "Edit section: Junctional arrhythmia")\] - [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") - [Junctional rhythm](https://en.wikipedia.org/wiki/Junctional_rhythm "Junctional rhythm") - [Junctional tachycardia](https://en.wikipedia.org/wiki/Junctional_tachycardia "Junctional tachycardia") - [Premature junctional contraction](https://en.wikipedia.org/wiki/Premature_junctional_contraction "Premature junctional contraction") ### Ventricular arrhythmia \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=4 "Edit section: Ventricular arrhythmia")\] - [Premature ventricular contractions](https://en.wikipedia.org/wiki/Premature_ventricular_contraction "Premature ventricular contraction") (PVCs), sometimes called ventricular extra beats (VEBs) - Premature ventricular beats occurring after every normal beat are termed [ventricular bigeminy](https://en.wikipedia.org/wiki/Ventricular_bigeminy "Ventricular bigeminy") - PVCs that occur at intervals of 2 normal beats to 1 PVC, or 1 normal beat to 2 PVCs, are termed "PVCs in trigeminy"[\[13\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Farzam-13) - Groups of three premature ventricular beats are called triplets and are considered a brief run of [non-sustained ventricular tachycardia](https://en.wikipedia.org/wiki/Non-sustained_ventricular_tachycardia "Non-sustained ventricular tachycardia") (NSVT); if the grouping lasts for more than 30 seconds, it is considered sustained [ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia") (VT).[\[14\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-wagnerNSVT-14) - [Accelerated idioventricular rhythm](https://en.wikipedia.org/wiki/Accelerated_idioventricular_rhythm "Accelerated idioventricular rhythm") - [Monomorphic ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia") - [Polymorphic ventricular tachycardia](https://en.wikipedia.org/wiki/Polymorphic_ventricular_tachycardia "Polymorphic ventricular tachycardia") - [Ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") - [Torsades de pointes](https://en.wikipedia.org/wiki/Torsades_de_pointes "Torsades de pointes") - [Arrhythmogenic right ventricular dysplasia](https://en.wikipedia.org/wiki/Arrhythmogenic_right_ventricular_dysplasia "Arrhythmogenic right ventricular dysplasia") - [Re-entry ventricular arrhythmia](https://en.wikipedia.org/wiki/Re-entry_ventricular_arrhythmia "Re-entry ventricular arrhythmia") [Heart blocks](https://en.wikipedia.org/wiki/Heart_block "Heart block") are also known as [AV](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node") blocks, because the vast majority of them arise from pathology at the [atrioventricular node](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node"). They are the most common causes of bradycardia:\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] - [First-degree heart block](https://en.wikipedia.org/wiki/First-degree_heart_block "First-degree heart block"), which manifests as PR prolongation - [Second-degree heart block](https://en.wikipedia.org/wiki/Second-degree_heart_block "Second-degree heart block") - [Type 1 Second degree heart block](https://en.wikipedia.org/wiki/Type_1_Second_degree_heart_block "Type 1 Second degree heart block"), also known as [Mobitz I](https://en.wikipedia.org/wiki/Mobitz_I "Mobitz I") or [Wenckebach](https://en.wikipedia.org/wiki/Wenckebach "Wenckebach") - [Type 2 Second degree heart block](https://en.wikipedia.org/wiki/Type_2_Second_degree_heart_block "Type 2 Second degree heart block"), also known as [Mobitz II](https://en.wikipedia.org/wiki/Mobitz_II "Mobitz II") - [Third-degree heart block](https://en.wikipedia.org/wiki/Third-degree_heart_block "Third-degree heart block"), also known as [complete heart block](https://en.wikipedia.org/wiki/Complete_heart_block "Complete heart block") First, second, and third-degree blocks also can occur at the level of the sinoatrial junction. This is referred to as [sinoatrial block](https://en.wikipedia.org/wiki/Sinoatrial_block "Sinoatrial block") typically manifesting with various degrees and patterns of [sinus bradycardia](https://en.wikipedia.org/wiki/Sinus_bradycardia "Sinus bradycardia").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] ### Sudden arrhythmic death syndrome \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=6 "Edit section: Sudden arrhythmic death syndrome")\] [Sudden arrhythmic death syndrome](https://en.wikipedia.org/wiki/Sudden_arrhythmic_death_syndrome "Sudden arrhythmic death syndrome") (SADS), is a term used as part of sudden unexpected death syndrome to describe sudden [death](https://en.wikipedia.org/wiki/Death "Death") because of [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest") occasioned by an arrhythmia in the presence or absence of any structural heart disease on autopsy. The most common cause of sudden death in the US is [coronary artery disease](https://en.wikipedia.org/wiki/Coronary_artery_disease "Coronary artery disease") specifically because of poor oxygenation of the heart muscle, that is [myocardial ischemia](https://en.wikipedia.org/wiki/Myocardial_ischemia "Myocardial ischemia") or a [heart attack](https://en.wikipedia.org/wiki/Myocardial_infarction "Myocardial infarction")[\[15\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-15) Approximately 180,000 to 250,000 people die suddenly of this cause every year in the US. SADS may occur from other causes. There are many inherited conditions and heart diseases that can affect young people which can subsequently cause sudden death without advance symptoms.[\[16\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-16) Causes of SADS in young people include [viral myocarditis](https://en.wikipedia.org/wiki/Viral_myocarditis "Viral myocarditis"), [long QT syndrome](https://en.wikipedia.org/wiki/Long_QT_syndrome "Long QT syndrome"), [Brugada syndrome](https://en.wikipedia.org/wiki/Brugada_syndrome "Brugada syndrome"), [Catecholaminergic polymorphic ventricular tachycardia](https://en.wikipedia.org/wiki/Catecholaminergic_polymorphic_ventricular_tachycardia "Catecholaminergic polymorphic ventricular tachycardia"), [hypertrophic cardiomyopathy](https://en.wikipedia.org/wiki/Hypertrophic_cardiomyopathy "Hypertrophic cardiomyopathy") and [arrhythmogenic right ventricular dysplasia](https://en.wikipedia.org/wiki/Arrhythmogenic_right_ventricular_dysplasia "Arrhythmogenic right ventricular dysplasia").[\[17\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Chugh-2008-17)[\[18\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-18) Arrhythmias may also occur in the [fetus](https://en.wikipedia.org/wiki/Fetus "Fetus").[\[19\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Batra-19) The normal heart rate of the fetus is between 110 and 160 beats per minute. Any rhythm beyond these limits is abnormal and classed as a fetal arrhythmia. These are mainly the result of premature atrial contractions, usually give no symptoms, and have little consequence. However, around one percent of these will be the result of significant structural damage to the heart.[\[19\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Batra-19) The term cardiac arrhythmia covers a very large number of very different conditions.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] The most common symptom of arrhythmia is an awareness of an abnormal heartbeat, called [palpitations](https://en.wikipedia.org/wiki/Palpitation "Palpitation"). These may be infrequent, frequent, or continuous. Some of these arrhythmias are harmless (though [distracting](https://en.wikipedia.org/wiki/Distracting "Distracting") for patients) but some of them predispose to adverse outcomes. Arrhythmias also cause [chest pain](https://en.wikipedia.org/wiki/Chest_pain "Chest pain") and [shortness of breath](https://en.wikipedia.org/wiki/Shortness_of_breath "Shortness of breath").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Some arrhythmias do not cause symptoms and are not associated with increased mortality. However, some asymptomatic arrhythmias are associated with adverse events. Examples include a higher risk of blood clotting within the heart and a higher risk of insufficient blood being transported to the heart because of a weak heartbeat. Other increased risks are of [embolization](https://en.wikipedia.org/wiki/Embolization "Embolization") and stroke, heart failure, and sudden cardiac death.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] If an arrhythmia results in a heartbeat that is too fast, too slow, or too weak to supply the body's needs, this manifests as lower blood pressure and may cause lightheadedness, dizziness, syncope, loss of consciousness, [coma](https://en.wikipedia.org/wiki/Coma "Coma"), [persistent vegetative state](https://en.wikipedia.org/wiki/Persistent_vegetative_state "Persistent vegetative state"), or brain death due to insufficient supply of blood and oxygen to the brain.[\[20\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-20) Some types of arrhythmia result in [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest"), or sudden death.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Medical assessment of the abnormality using an [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") is one way to diagnose and assess the risk of any given arrhythmia.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Cardiac arrhythmia are caused by one of two major mechanisms. The first of arrhythmia is a result of enhanced or abnormal [impulse](https://en.wikipedia.org/wiki/Cardiac_action_potential "Cardiac action potential") formation originating at the [pacemaker](https://en.wikipedia.org/wiki/Cardiac_pacemaker "Cardiac pacemaker") or the [His](https://en.wikipedia.org/wiki/Bundle_of_His "Bundle of His")\-[Purkinje](https://en.wikipedia.org/wiki/Purkinje_fibers "Purkinje fibers") network. The second is due to [re-entry](https://en.wikipedia.org/wiki/Arrhythmia#Re-entry) conduction disturbances.[\[21\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Antzelevitch_2011-21) Cardiac arrhythmia is often first detected by simple but nonspecific means: [auscultation](https://en.wikipedia.org/wiki/Auscultation "Auscultation") of the heartbeat with a [stethoscope](https://en.wikipedia.org/wiki/Stethoscope "Stethoscope"), or feeling for peripheral [pulses](https://en.wikipedia.org/wiki/Pulse "Pulse"). These cannot usually diagnose specific arrhythmia but can give a general indication of the heart rate and whether it is regular or irregular. Not all the electrical impulses of the heart produce audible or palpable beats; in many cardiac arrhythmias, the premature or abnormal beats do not produce an effective pumping action and are experienced as "skipped" beats.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] The simplest specific diagnostic test for assessment of heart rhythm is the [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiogram "Electrocardiogram") (abbreviated ECG or EKG).[\[22\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-22)[\[23\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-23) A [Holter monitor](https://en.wikipedia.org/wiki/Holter_monitor "Holter monitor") is an EKG recorded over a 24-hour period, to detect arrhythmias that may happen briefly and unpredictably throughout the day.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] A more advanced study of the heart's electrical activity can be performed to assess the source of the [aberrant](https://en.wikipedia.org/wiki/Cardiac_aberration "Cardiac aberration") heart beats. This can be accomplished in an [electrophysiology study](https://en.wikipedia.org/wiki/Electrophysiology_study "Electrophysiology study"), an [endovascular procedure](https://en.wikipedia.org/wiki/Endovascular_procedure "Endovascular procedure") that uses a catheter to "listen" to the electrical activity from within the heart, additionally if the source of the arrhythmias is found, often the abnormal cells can be ablated and the arrhythmia can be permanently corrected. Transesophageal atrial stimulation (TAS) instead uses an electrode inserted through the [esophagus](https://en.wikipedia.org/wiki/Esophagus "Esophagus") to a part where the distance to the posterior wall of the [left atrium](https://en.wikipedia.org/wiki/Left_atrium "Left atrium") is only approximately 5–6 mm (remaining constant in people of different age and weight).[\[24\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-MeigasKaik2008-24) Transesophageal atrial stimulation can differentiate between [atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter"), [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") and orthodromic [atrioventricular reentrant tachycardia](https://en.wikipedia.org/wiki/Atrioventricular_reentrant_tachycardia "Atrioventricular reentrant tachycardia").[\[25\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25) It can also evaluate the risk in people with [Wolff–Parkinson–White syndrome](https://en.wikipedia.org/wiki/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome "Wolff–Parkinson–White syndrome"), as well as terminate [supraventricular tachycardia](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia") caused by [re-entry](https://en.wikipedia.org/wiki/Cardiac_arrhythmia#Re-entry "Cardiac arrhythmia").[\[25\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-PehrsonBlomstr%C3%B6-LUNDQVIST1994-25) ### Differential diagnosis \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=11 "Edit section: Differential diagnosis")\] #### Normal electrical activity \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=12 "Edit section: Normal electrical activity")\] Each heartbeat originates as an electrical impulse from a small area of tissue in the right [atrium](https://en.wikipedia.org/wiki/Atrium_\(heart\) "Atrium (heart)") of the heart called the [sinus node or sinoatrial node (SA node)](https://en.wikipedia.org/wiki/Sinoatrial_node "Sinoatrial node"). The impulse initially causes both atria to contract, then activates the [atrioventricular node (AV node)](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node"), which is normally the only electrical connection between the atria and the [ventricles](https://en.wikipedia.org/wiki/Ventricle_\(heart\) "Ventricle (heart)") (main pumping chambers). The impulse then spreads through both ventricles via the [bundle of His](https://en.wikipedia.org/wiki/Bundle_of_His "Bundle of His") and the [Purkinje fibers](https://en.wikipedia.org/wiki/Purkinje_fibers "Purkinje fibers") causing a synchronized contraction of the heart muscle and, thus, the pulse.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] In adults, the normal resting heart rate ranges from 60 to 90 beats per minute. The resting heart rate in children is much faster. In athletes, however, the resting heart rate can be as slow as 40 beats per minute, and be considered normal.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] The term [sinus arrhythmia](https://en.wikipedia.org/wiki/Respiratory_sinus_arrhythmia "Respiratory sinus arrhythmia")[\[26\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-26) refers to a normal phenomenon of alternating mild acceleration and slowing of the heart rate that occurs with breathing in and out respectively. It is usually quite pronounced in children and steadily decreases with age. This can also be present during [meditation](https://en.wikipedia.org/wiki/Meditation "Meditation") breathing exercises that involve deep inhaling and breath holding patterns.[\[27\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-27) [![](https://upload.wikimedia.org/wikipedia/commons/thumb/1/1f/Sinus_pause.PNG/250px-Sinus_pause.PNG)](https://en.wikipedia.org/wiki/File:Sinus_pause.PNG) Normal sinus rhythm, with solid black arrows pointing to normal P waves representative of normal sinus node function, followed by a pause in sinus node activity (resulting in a transient loss of heartbeats). Note that the P wave that disrupts the pause (indicated by the dashed arrow) does not look like the previous (normal) P waves – this last P wave is arising from a different part of the atrium, representing an escape rhythm. A slow rhythm (less than 60 beats/min) is labelled [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia"). This may be caused by a slowed signal from the sinus node (sinus bradycardia), by a pause in the normal activity of the sinus node (sinus arrest), or by blocking of the electrical impulse on its way from the atria to the ventricles (AV block or heart block). Heart block comes in varying degrees and severity. It may be caused by reversible poisoning of the AV node (with drugs that impair conduction) or by irreversible damage to the node. Bradycardias may also be present in the normally functioning heart of endurance athletes or other well-conditioned persons. Bradycardia may also occur in [some types of seizures](https://en.wikipedia.org/wiki/Ictal_bradycardia "Ictal bradycardia").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] In adults and children over 15, resting heart rate faster than 100 beats per minute is labeled [tachycardia](https://en.wikipedia.org/wiki/Tachycardia "Tachycardia"). Tachycardia may result in palpitation; however, tachycardia is not necessarily an arrhythmia. Increased heart rate is a normal response to physical exercise or emotional stress. This is mediated by the [sympathetic nervous system](https://en.wikipedia.org/wiki/Sympathetic_nervous_system "Sympathetic nervous system") on the [sinus node](https://en.wikipedia.org/wiki/Sinus_node "Sinus node") and called sinus tachycardia. Other conditions that increase sympathetic nervous system activity in the heart include ingested or injected substances, such as [caffeine](https://en.wikipedia.org/wiki/Caffeine "Caffeine") or [amphetamines](https://en.wikipedia.org/wiki/Amphetamines "Amphetamines"), and an overactive thyroid gland ([hyperthyroidism](https://en.wikipedia.org/wiki/Hyperthyroidism "Hyperthyroidism")) or [anemia](https://en.wikipedia.org/wiki/Anemia "Anemia").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Tachycardia that is not sinus tachycardia usually results from the addition of abnormal impulses to the normal [cardiac cycle](https://en.wikipedia.org/wiki/Cardiac_cycle "Cardiac cycle"). Abnormal impulses can begin by one of three mechanisms: automaticity, re-entry, or triggered activity. A specialized form of re-entry which is both common and problematic is termed fibrillation.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Although the term "tachycardia" has been known for over 160 years, bases for the classification of arrhythmias are still being discussed.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Congenital heart defects are structural or electrical pathway problems in the heart that are present at birth. Anyone can be affected by this because overall health does not play a role in the problem. Problems with the electrical pathway of the heart can cause very fast or even deadly arrhythmias. [Wolff–Parkinson–White syndrome](https://en.wikipedia.org/wiki/Wolff%E2%80%93Parkinson%E2%80%93White_syndrome "Wolff–Parkinson–White syndrome") is due to an extra pathway in the heart that is made up of electrical muscle tissue. This tissue allows the electrical impulse, which stimulates the heartbeat, to happen very rapidly. Right [ventricular outflow tract](https://en.wikipedia.org/wiki/Ventricular_outflow_tract "Ventricular outflow tract") tachycardia is the most common type of ventricular tachycardia in otherwise healthy individuals. This defect is due to an electrical node in the right ventricle just before the pulmonary artery. When the node is stimulated, the patient will go into ventricular tachycardia, which does not allow the heart to fill with blood before beating again. [Long QT syndrome](https://en.wikipedia.org/wiki/Long_QT_syndrome "Long QT syndrome") is another complex problem in the heart and has been labeled as an independent factor in mortality. There are multiple methods of treatment for these including cardiac ablations, medication treatment, or lifestyle changes to have less stress and exercise.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Automaticity refers to a [cardiac muscle](https://en.wikipedia.org/wiki/Cardiac_muscle "Cardiac muscle") cell firing off an impulse on its own. All of the cells in the heart have the ability to initiate an [action potential](https://en.wikipedia.org/wiki/Action_potential "Action potential"); however, only some of these cells are designed to routinely trigger heartbeats. These cells are found in the conduction system of the heart and include the SA node, AV node, Bundle of His, and Purkinje fibers. The [sinoatrial node](https://en.wikipedia.org/wiki/Sinoatrial_node "Sinoatrial node") is a single specialized location in the atrium that has a higher automaticity (a faster pacemaker) than the rest of the heart and, therefore, is usually responsible for setting the heart rate and initiating each heartbeat.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Any part of the heart that initiates an impulse without waiting for the sinoatrial node is called an [ectopic](https://en.wikipedia.org/wiki/Cardiac_ectopy "Cardiac ectopy") focus and is, by definition, a pathological phenomenon. This may cause a single premature beat now and then, or, if the [ectopic focus](https://en.wikipedia.org/wiki/Ectopic_focus "Ectopic focus") fires more often than the sinoatrial node, it can produce a sustained abnormal rhythm. Rhythms produced by an ectopic focus in the atria, or by the [atrioventricular node](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node"), are the least dangerous dysrhythmias; but they can still produce a decrease in the heart's pumping efficiency because the signal reaches the various parts of the heart muscle with different timing than usual and can be responsible for poorly coordinated contraction.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Conditions that increase automaticity include [sympathetic nervous system](https://en.wikipedia.org/wiki/Sympathetic_nervous_system "Sympathetic nervous system") stimulation and [hypoxia](https://en.wikipedia.org/wiki/Hypoxia_\(medical\) "Hypoxia (medical)"). The resulting heart rhythm depends on where the first signal begins: If it is the sinoatrial node, the rhythm remains normal but rapid; if it is an ectopic focus, many types of dysrhythmia may ensue. Re-entrant arrhythmias occur when an electrical impulse recurrently travels in a tight circle within the heart, rather than moving from one end of the heart to the other and then stopping.[\[28\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Wiener-1946-28)[\[29\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Allessie-1976-29) Every cardiac cell can transmit [impulses of excitation](https://en.wikipedia.org/wiki/Autowave "Autowave") in every direction but will do so only once within a short time. Normally, the [action potential](https://en.wikipedia.org/wiki/Action_potential "Action potential") impulse will spread through the heart quickly enough that each cell will respond only once. However, if there is some essential heterogeneity of [refractory period](https://en.wikipedia.org/wiki/Refractory_period_\(physiology\) "Refractory period (physiology)") or if conduction is abnormally slow in some areas (for example in heart damage) so the myocardial cells are unable to activate the fast sodium channel, part of the impulse will arrive late and potentially be treated as a new impulse. Depending on the timing, this can produce a sustained abnormal circuit rhythm. As a sort of re-entry, vortices of excitation in the myocardium ([autowave vortices](https://en.wikipedia.org/wiki/Autowave "Autowave")) are considered to be the main mechanism of life-threatening cardiac arrhythmias.[\[30\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-b-Mandel-1995-30) In particular, the [autowave reverberator](https://en.wikipedia.org/wiki/Autowave_reverberator "Autowave reverberator") is common in the thin walls of the atria, sometimes resulting in [atrial flutter](https://en.wikipedia.org/wiki/Atrial_flutter "Atrial flutter"). Re-entry is also responsible for most [paroxysmal supraventricular tachycardia](https://en.wikipedia.org/wiki/Paroxysmal_supraventricular_tachycardia "Paroxysmal supraventricular tachycardia"), and dangerous [ventricular tachycardia](https://en.wikipedia.org/wiki/Ventricular_tachycardia "Ventricular tachycardia"). These types of re-entry circuits are different from [WPW](https://en.wikipedia.org/wiki/WPW "WPW") syndromes, which utilize abnormal conduction pathways. Although [omega-3 fatty acids](https://en.wikipedia.org/wiki/Omega-3_fatty_acid "Omega-3 fatty acid") from [fish oil](https://en.wikipedia.org/wiki/Fish_oil "Fish oil") can be protective against arrhythmias, they can facilitate re-entrant arrhythmias.[\[31\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-a-_Coronel-2007-31) When an entire chamber of the heart is involved in multiple micro-re-entry circuits and is, therefore, quivering with chaotic electrical impulses, it is said to be in fibrillation. Fibrillation can affect the atrium ([atrial fibrillation](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation")) or the ventricle ([ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation")): ventricular fibrillation is imminently life-threatening. - Atrial fibrillation affects the upper chambers of the heart, known as the [atria](https://en.wikipedia.org/wiki/Atrium_\(heart\) "Atrium (heart)"). Atrial fibrillation may be due to serious underlying medical conditions and should be evaluated by a [physician](https://en.wikipedia.org/wiki/Physician "Physician"). It is not typically a medical emergency. - Ventricular fibrillation occurs in the [ventricles](https://en.wikipedia.org/wiki/Ventricle_\(heart\) "Ventricle (heart)") (lower chambers) of the heart; it is always a medical emergency. If left untreated, [ventricular fibrillation](https://en.wikipedia.org/wiki/Ventricular_fibrillation "Ventricular fibrillation") (VF, or V-fib) can lead to death within minutes. When a heart goes into V-fib, effective pumping of the blood stops. V-fib is considered a form of [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest"). An affected individual will not survive unless [cardiopulmonary resuscitation](https://en.wikipedia.org/wiki/Cardiopulmonary_resuscitation "Cardiopulmonary resuscitation") (CPR) and [defibrillation](https://en.wikipedia.org/wiki/Defibrillation "Defibrillation") are provided immediately. CPR can prolong the survival of the [brain](https://en.wikipedia.org/wiki/Brain "Brain") in the lack of a normal pulse, but defibrillation is the only intervention that can restore a healthy heart rhythm. Defibrillation is performed by applying an electric shock to the heart, which resets the cells, permitting a normal beat to re-establish itself. Triggered beats occur when problems at the level of the ion channels in individual heart cells result in abnormal propagation of electrical activity and can lead to a sustained abnormal rhythm. They are relatively rare and can result from the action of anti-arrhythmic drugs, or after [depolarizations](https://en.wikipedia.org/wiki/Depolarization "Depolarization").\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] The method of cardiac rhythm management depends firstly on whether the affected person is stable or unstable. Treatments may include physical maneuvers, medications, electricity conversion, or electro- or cryo-cautery.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] In the United States, people admitted to the hospital with cardiac arrhythmia and conduction disorders with and without complications were admitted to the intensive care unit more than half the time in 2011.[\[32\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-32) Several physical acts can increase parasympathetic nervous supply to the heart, resulting in blocking of electrical conduction through the AV node. This can slow down or stop several arrhythmias that originate above or at the AV node (see main article: [supraventricular tachycardias](https://en.wikipedia.org/wiki/Supraventricular_tachycardia "Supraventricular tachycardia")). Parasympathetic nervous supply to the heart is via the [vagus nerve](https://en.wikipedia.org/wiki/Vagus_nerve "Vagus nerve"), and these maneuvers are collectively known as [vagal maneuvers](https://en.wikipedia.org/wiki/Vagal_maneuver "Vagal maneuver"). ### Antiarrhythmic drugs \[[edit](https://en.wikipedia.org/w/index.php?title=Arrhythmia&action=edit&section=22 "Edit section: Antiarrhythmic drugs")\] There are many classes of antiarrhythmic medications, with different mechanisms of action and many different individual drugs within these classes. Although the goal of drug therapy is to prevent arrhythmia, nearly every antiarrhythmic drug has the potential to act as a [pro-arrhythmic](https://en.wikipedia.org/wiki/Pro-arrhythmic "Pro-arrhythmic"), and so must be carefully selected and used under medical supervision. Several groups of drugs slow conduction through the heart, without actually preventing an arrhythmia. These drugs can be used to "rate control" a fast rhythm and make it physically tolerable for the patient.\[[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed "Wikipedia:Citation needed")\] Some arrhythmias promote blood clotting within the heart and increase the risk of embolus and stroke. [Anticoagulant](https://en.wikipedia.org/wiki/Anticoagulant "Anticoagulant") medications such as [warfarin](https://en.wikipedia.org/wiki/Warfarin "Warfarin") and [heparins](https://en.wikipedia.org/wiki/Heparin "Heparin"), and anti-platelet drugs such as [aspirin](https://en.wikipedia.org/wiki/Aspirin "Aspirin") can reduce the risk of clotting. Arrhythmias may also be treated electrically, by applying a shock across the heart – either externally to the chest wall, or internally to the heart via implanted electrodes.[\[33\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-33) [Cardioversion](https://en.wikipedia.org/wiki/Cardioversion "Cardioversion") is either achieved pharmacologically or via the application of a shock synchronized to the underlying heartbeat. It is used for the treatment of supraventricular tachycardias. In elective cardioversion, the recipient is usually sedated or lightly [anesthetized](https://en.wikipedia.org/wiki/Anesthesia "Anesthesia") for the procedure. [Defibrillation](https://en.wikipedia.org/wiki/Defibrillation "Defibrillation") differs in that the shock is not synchronized. It is needed for the chaotic rhythm of ventricular fibrillation and is also used for pulseless ventricular tachycardia. Often, more electricity is required for defibrillation than for cardioversion. In most defibrillation, the recipient has lost consciousness so there is no need for sedation. Defibrillation or cardioversion may be accomplished by an [implantable cardioverter-defibrillator](https://en.wikipedia.org/wiki/Implantable_cardioverter-defibrillator "Implantable cardioverter-defibrillator") (ICD). Electrical treatment of arrhythmias also includes [cardiac pacing](https://en.wikipedia.org/wiki/Cardiac_pacing "Cardiac pacing"). Temporary pacing may be necessary for reversible causes of very slow heartbeats, or [bradycardia](https://en.wikipedia.org/wiki/Bradycardia "Bradycardia") (for example, from [drug overdose](https://en.wikipedia.org/wiki/Drug_overdose "Drug overdose") or [myocardial infarction](https://en.wikipedia.org/wiki/Myocardial_infarction "Myocardial infarction")). A permanent [pacemaker](https://en.wikipedia.org/wiki/Artificial_pacemaker "Artificial pacemaker") may be placed in situations where the bradycardia is not expected to recover. Some cardiologists further sub-specialize into electrophysiology. In specialized [catheter laboratories](https://en.wikipedia.org/wiki/Catheter "Catheter"), they use fine probes inserted through the blood vessels to map electrical activity from within the heart. This allows abnormal areas of conduction to be located very accurately and subsequently destroyed by heat, cold, electrical, or laser probes in a process called [catheter ablation](https://en.wikipedia.org/wiki/Catheter_ablation "Catheter ablation"). This procedure may be completely curative for some forms of arrhythmia, but for others, the success rate remains disappointing. [AV nodal reentrant tachycardia](https://en.wikipedia.org/wiki/AV_nodal_reentrant_tachycardia "AV nodal reentrant tachycardia") is often curable by ablating one of the pathways in the [AV node](https://en.wikipedia.org/wiki/Atrioventricular_node "Atrioventricular node") (usually the slow pathway). [Atrial fibrillation](https://en.wikipedia.org/wiki/Atrial_fibrillation "Atrial fibrillation") can also be treated, by performing a [pulmonary vein](https://en.wikipedia.org/wiki/Pulmonary_vein "Pulmonary vein") isolation, but the results are less reliable. Arrhythmias due to medications have been reported since the 1920s with the use of [quinine](https://en.wikipedia.org/wiki/Quinine "Quinine").[\[34\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Hei2010-34) In the 1960s and 1970s problems with antihistamines and antipsychotics were discovered.[\[34\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Hei2010-34) It was not until the 1980s that the underlying issue, [QTc prolongation](https://en.wikipedia.org/wiki/QT_interval#Abnormal_intervals "QT interval") was determined.[\[34\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-Hei2010-34) [Osborn waves](https://en.wikipedia.org/wiki/J_wave "J wave") on [electrocardiogram](https://en.wikipedia.org/wiki/Electrocardiography "Electrocardiography") ([ECG](https://en.wikipedia.org/wiki/ECG "ECG")) are frequent during [targeted temperature management (TTM)](https://en.wikipedia.org/wiki/Targeted_temperature_management "Targeted temperature management") after [cardiac arrest](https://en.wikipedia.org/wiki/Cardiac_arrest "Cardiac arrest"), particularly in patients treated with 33 °C.[\[35\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-:0-35) [Osborn waves](https://en.wikipedia.org/wiki/J_wave "J wave") are not associated with increased risk of [ventricular arrhythmia](https://en.wikipedia.org/wiki/Ventricular_arrhythmia "Ventricular arrhythmia"), and may be considered a [benign](https://en.wikipedia.org/wiki/Benign_early_repolarization "Benign early repolarization") physiological phenomenon, associated with lower [mortality](https://en.wikipedia.org/wiki/Mortality_rate "Mortality rate") in univariable analyses.[\[35\]](https://en.wikipedia.org/wiki/Arrhythmia#cite_note-:0-35) - [Pre-excitation syndrome](https://en.wikipedia.org/wiki/Pre-excitation_syndrome "Pre-excitation syndrome") - [Holiday heart syndrome](https://en.wikipedia.org/wiki/Holiday_heart_syndrome "Holiday heart syndrome") 1. ^ [*a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Sym_1-3) ["What Are the Signs and Symptoms of an Arrhythmia?"](https://www.nhlbi.nih.gov/health/arrhythmias/symptoms). National Heart, Lung, and Blood Institute. July 1, 2011. [Archived](https://web.archive.org/web/20150219081446/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/signs) from the original on 19 February 2015. Retrieved 7 March 2015. 2. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-3) [e](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-4) [f](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-5) [g](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Def_2-6) ["What Is Arrhythmia?"](https://web.archive.org/web/20150302074103/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/). [National Heart, Lung, and Blood Institute](https://en.wikipedia.org/wiki/National_Heart,_Lung,_and_Blood_Institute "National Heart, Lung, and Blood Institute"). July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr) on 2 March 2015. Retrieved 7 March 2015. 3. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-3) [e](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-4) [f](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-5) [g](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-6) [h](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-7) [i](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Type_3-8) ["Types of Arrhythmia"](https://web.archive.org/web/20150607165144/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/types). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/types) on 7 June 2015. Retrieved 7 March 2015. 4. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Risk_4-3) ["Who Is at Risk for an Arrhythmia?"](https://web.archive.org/web/20150303190136/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/atrisk). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/atrisk) on 3 March 2015. Retrieved 7 March 2015. 5. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Diag_5-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Diag_5-1) ["How Are Arrhythmias Diagnosed?"](https://web.archive.org/web/20150218075708/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/diagnosis). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/diagnosis) on 18 February 2015. Retrieved 7 March 2015. 6. ^ [a](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-0) [b](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-1) [c](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-2) [d](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-3) [e](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-4) [f](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-5) [g](https://en.wikipedia.org/wiki/Arrhythmia#cite_ref-NIH2011Tx_6-6) ["How Are Arrhythmias Treated?"](https://web.archive.org/web/20150217135319/http://www.nhlbi.nih.gov/health/health-topics/topics/arr/treatment). National Heart, Lung, and Blood Institute. July 1, 2011. Archived from [the original](http://www.nhlbi.nih.gov/health/health-topics/topics/arr/treatment) on 17 February 2015. Retrieved 7 March 2015. 7. 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