🕷️ Crawler Inspector

URL Lookup

Direct Parameter Lookup

Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 11 (from laksa174)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa011.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://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia\')), getAhrefsUnparsedNoserviceFromURL(\'https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia","crawl_time":1775730269,"first_indexed_time":1533016309,"http_code":200,"src_unparsed":"org,heart!www,\/en\/health-topics\/arrhythmia\/about-arrhythmia s443","src_root_hash":"6217059405564628611","history_drop_reason":null,"meta_title":"What is an Arrhythmia? | American Heart Association","meta_descriptions":["What is an arrhythmia? The American Heart Association explains that arrhythmia refers to any problem in the rate and\/or rhythm of a person’s heartbeat, such as atrial fibrillation, bradycardia, tachycardia, conduction disorders, rhythm disorders, ventricular fibrillation, premature contractions and more."],"attrs_boilerpipe_text":"The term “arrhythmia” refers to any problem in the rate or rhythm of a person’s heartbeat. During an arrhythmia, the electrical impulses may be too fast, too slow or erratic, causing an irregular heartbeat.\nWhen the heart doesn’t beat properly, it can’t pump blood effectively. When this happens, the lungs, brain and all other organs can’t work properly and may shut down or be damaged. \nView an animation of arrhythmia\n.\nTypes of Arrhythmias\nAtrial Fibrillation\nAtrial Flutter\nBradycardia\nConduction Disorders\n \nPremature Contraction\nTachycardia\n      \nVentricular Fibrillation\n     \nOther Rhythm Disorders\nTypes of Arrhythmias in Children\nThe normal heart is a strong, muscular pump about the size of a fist. It pumps blood to all parts of the body.   \nTo understand how the heart pumps, learn about: Structure of the heart\nWatch an animation of heart valve anatomy\nThe heart: Four chambers, four valves\nThe heart has four chambers, two on the right and two on the left:\nTwo upper chambers are called atria (one is called an atrium).\nTwo lower chambers are called ventricles. \nThe heart also has four valves that open and close to let blood flow in only one direction when the heart contracts (beats). The four heart valves are: \nTricuspid valve, located between the right atrium and right ventricle\nPulmonary or pulmonic valve, between the right ventricle and the pulmonary artery\nMitral valve, between the left atrium and left ventricle\nAortic valve, between the left ventricle and the aorta \nEach valve has a set of flaps (also called leaflets or cusps). The mitral valve has two flaps; the others have three. Blood flow occurs only when there’s a difference in pressure across the valves, which causes them to open. Under normal conditions, the valves allow blood to flow in only one direction.\nThe heart pumps blood to the lungs and to all the body’s tissues by a sequence of highly organized contractions of the four chambers. For the heart to function properly, the four chambers must beat in an organized way.\nElectrical system of the heart\nElectrical signals control the pump\nThe heartbeat (contraction) begins when an electrical impulse from the sinus node (also called SA node) moves through the heart’s muscle tissue. The SA node is sometimes called the heart’s “natural pacemaker” because it starts the impulses for the heartbeat.\nThe normal electrical sequence begins in the right atrium and spreads throughout the atria to the atrioventricular (AV) node. Electrical impulses travel down the bundle of His from the AV node and through the Purkinje fibers, causing the ventricles to contract.\nThe normal heart beats in a regular manner because electrical impulses cause a sequence of organized contractions. In an adult, a normal heart beats 60 to 100 times a minute.\nElectrocardiography (ECG or EKG)\n is a simple, painless test that records the heart’s electrical activity and can help detect arrhythmias (abnormal heart rhythms).\nAbnormal heart rhythms (arrhythmias)\nArrhythmias are abnormal heartbeats. The term “arrhythmia” refers to any change from the normal sequence of electrical impulses.\nSome arrhythmias are so brief (such as a temporary pause or premature beat) that the overall heart rate or rhythm isn’t greatly affected. But if arrhythmias last longer, they may make the heart rate too slow, too fast or erratic, so the heart pumps less effectively. \nA fast heart rate (in adults, more than 100 beats per minute) is called\ntachycardia\n.\nA slow heart rate (less than 60 beats per minute) is called \nbradycardia\n.\nCauses\nNormally, the heart’s most rapidly firing cells are in the sinus node, making that area a natural pacemaker. Under some conditions, almost all heart tissue can start an impulse of the type that can generate a heartbeat. \nCells in the heart’s conduction system can fire automatically and start electrical activity. This activity can interrupt the normal order of the heart’s pumping activity.  \nSecondary pacemakers elsewhere in the heart provide a “backup” rhythm when the sinus node doesn’t work properly or when impulses are blocked somewhere in the conduction system. \nArrhythmias can be caused by:\nA delay or blockage of the electrical signals that control the heartbeat\nAnother part of the heart taking over as pacemaker\nChanges to heart tissue caused by changes in blood flow, damage to the heart’s electrical system or stiffening or scarring of the heart tissue\nExcessive exertion, strain or stress\nAn imbalance of fluids, hormones or electrolytes in the blood\nCertain heart medications\nAn arrhythmia occurs when:\nThe heart’s natural pacemaker develops an abnormal rate or rhythm.\nThe normal conduction pathway is interrupted or changed.\nAnother part of the heart takes over as a pacemaker.","attrs_markdown":"[Skip to main content](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia#main-content)\n\n- [Heart Attack and Stroke Symptoms](https:\/\/www.heart.org\/en\/about-us\/heart-attack-and-stroke-symptoms)\n- [Volunteer](https:\/\/www.heart.org\/en\/volunteer)\n- [Learn CPR](https:\/\/cpr.heart.org\/en\/)\n- [ShopHeart](https:\/\/www.shopheart.org\/?utm_source=heart.org&utm_medium=Referral&utm_campaign=AHA-Parent-Site-Top-Nav-Desktop)\n\nMenu\n\nClose Menu\n\n- Healthy Living\n  - 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[Mental Health and Well-being](https:\/\/www.heart.org\/en\/healthy-living\/healthy-lifestyle\/mental-health-and-wellbeing)\n    - [Nutrition Education Lessons](https:\/\/www.heart.org\/en\/healthy-living\/healthy-lifestyle\/nutrition-education-lessons)\n    - [Quit Smoking\/Tobacco\/Vaping](https:\/\/www.heart.org\/en\/healthy-living\/healthy-lifestyle\/quit-smoking-tobacco)\n    - [Sleep](https:\/\/www.heart.org\/en\/healthy-living\/healthy-lifestyle\/sleep)\n    - [Stress Management](https:\/\/www.heart.org\/en\/healthy-living\/healthy-lifestyle\/stress-management)\n  - [Fitness](https:\/\/www.heart.org\/en\/healthy-living\/fitness)\n    - [Fitness Basics](https:\/\/www.heart.org\/en\/healthy-living\/fitness\/fitness-basics)\n    - [Getting Active](https:\/\/www.heart.org\/en\/healthy-living\/fitness\/getting-active)\n    - [Staying Motivated](https:\/\/www.heart.org\/en\/healthy-living\/fitness\/staying-motivated)\n    - [Walking](https:\/\/www.heart.org\/en\/healthy-living\/fitness\/walking)\n  - 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- [Donate Once](https:\/\/mygiving.heart.org\/-\/XMNFTTTW)\n    - [Donate Monthly](https:\/\/pages.heart.org\/drtv_helpheart?s_subsrc=site_nav)\n- About Us\n- Learn CPR\n  \n  [CPR and First Aid](https:\/\/cpr.heart.org\/en\/)\n\n- In Your Community\n\n- [Heart Attack and Stroke Symptoms](https:\/\/www.heart.org\/en\/about-us\/heart-attack-and-stroke-symptoms)\n\n- [Learn CPR](https:\/\/cpr.heart.org\/en\/)\n- [Volunteer](https:\/\/www.heart.org\/en\/volunteer)\n- [ShopHeart](https:\/\/www.shopheart.org\/?utm_source=heart.org&utm_medium=Referral&utm_campaign=AHA-Parent-Site-Top-Nav-Mobile)\n\n1. [Home](https:\/\/www.heart.org\/en\/)\n2. [Health Topics](https:\/\/www.heart.org\/en\/health-topics)\n3. [Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia)\n4. [About Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia)\n\n# What is an Arrhythmia?\n![couple on a beach](https:\/\/www.heart.org\/-\/media\/Images\/Health-Topics\/Arrhythmia\/couples-piggybacking-at-beach.jpg?sc_lang=en)\n\nThe term “arrhythmia” refers to any problem in the rate or rhythm of a person’s heartbeat. During an arrhythmia, the electrical impulses may be too fast, too slow or erratic, causing an irregular heartbeat.\n\nWhen the heart doesn’t beat properly, it can’t pump blood effectively. When this happens, the lungs, brain and all other organs can’t work properly and may shut down or be damaged. [View an animation of arrhythmia](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=arrhyt).\n\n[![arrhythmia](https:\/\/www.heart.org\/-\/media\/Images\/Health-Topics\/Arrhythmia\/Arrhythmias.jpg?sc_lang=en)](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=arrhyt)\n\n## Types of Arrhythmias\n- **[Atrial Fibrillation](https:\/\/www.heart.org\/en\/health-topics\/atrial-fibrillation)**\n- **[Atrial Flutter](https:\/\/www.heart.org\/en\/health-topics\/atrial-fibrillation\/what-is-atrial-fibrillation-afib-or-af\/atrial-flutter)**\n- **[Bradycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/bradycardia--slow-heart-rate)**\n- **[Conduction Disorders](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/conduction-disorders)**\n- **[Premature Contraction](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/premature-contractions-pacs-and-pvcs)**\n- **[Tachycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/tachycardia--fast-heart-rate)**\n- **[Ventricular Fibrillation](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/ventricular-fibrillation)**\n- [**Other Rhythm Disorders**](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/other-heart-rhythm-disorders)\n- [**Types of Arrhythmias in Children**](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/types-of-arrhythmia-in-children)\n\nThe normal heart is a strong, muscular pump about the size of a fist. It pumps blood to all parts of the body.\n\n## To understand how the heart pumps, learn about: Structure of the heart\n[![Heart valve anatomy animation](https:\/\/www.heart.org\/-\/media\/Images\/Health-Topics\/Watch-Learn-and-Live\/Valve-anatomy.jpg?sc_lang=en)](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=anatom)\n\n[Watch an animation of heart valve anatomy](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=anatom)\n\n### The heart: Four chambers, four valves\nThe heart has four chambers, two on the right and two on the left:\n\n- Two upper chambers are called atria (one is called an atrium).\n- Two lower chambers are called ventricles.\n\nThe heart also has four valves that open and close to let blood flow in only one direction when the heart contracts (beats). The four heart valves are:\n\n- Tricuspid valve, located between the right atrium and right ventricle\n- Pulmonary or pulmonic valve, between the right ventricle and the pulmonary artery\n- Mitral valve, between the left atrium and left ventricle\n- Aortic valve, between the left ventricle and the aorta\n\nEach valve has a set of flaps (also called leaflets or cusps). The mitral valve has two flaps; the others have three. Blood flow occurs only when there’s a difference in pressure across the valves, which causes them to open. Under normal conditions, the valves allow blood to flow in only one direction.\n\nThe heart pumps blood to the lungs and to all the body’s tissues by a sequence of highly organized contractions of the four chambers. For the heart to function properly, the four chambers must beat in an organized way.\n\n## Electrical system of the heart\n### Electrical signals control the pump\nThe heartbeat (contraction) begins when an electrical impulse from the sinus node (also called SA node) moves through the heart’s muscle tissue. The SA node is sometimes called the heart’s “natural pacemaker” because it starts the impulses for the heartbeat.\n\nThe normal electrical sequence begins in the right atrium and spreads throughout the atria to the atrioventricular (AV) node. Electrical impulses travel down the bundle of His from the AV node and through the Purkinje fibers, causing the ventricles to contract.\n\nThe normal heart beats in a regular manner because electrical impulses cause a sequence of organized contractions. In an adult, a normal heart beats 60 to 100 times a minute.\n\n[Electrocardiography (ECG or EKG)](https:\/\/www.heart.org\/en\/health-topics\/heart-attack\/diagnosing-a-heart-attack\/electrocardiogram) is a simple, painless test that records the heart’s electrical activity and can help detect arrhythmias (abnormal heart rhythms).\n\n### Abnormal heart rhythms (arrhythmias)\nArrhythmias are abnormal heartbeats. The term “arrhythmia” refers to any change from the normal sequence of electrical impulses.\n\nSome arrhythmias are so brief (such as a temporary pause or premature beat) that the overall heart rate or rhythm isn’t greatly affected. But if arrhythmias last longer, they may make the heart rate too slow, too fast or erratic, so the heart pumps less effectively.\n\n- A fast heart rate (in adults, more than 100 beats per minute) is called [tachycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/tachycardia--fast-heart-rate).\n- A slow heart rate (less than 60 beats per minute) is called [bradycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/bradycardia--slow-heart-rate).\n#### ***Causes***\nNormally, the heart’s most rapidly firing cells are in the sinus node, making that area a natural pacemaker. Under some conditions, almost all heart tissue can start an impulse of the type that can generate a heartbeat.\n\n- Cells in the heart’s conduction system can fire automatically and start electrical activity. This activity can interrupt the normal order of the heart’s pumping activity.\n- Secondary pacemakers elsewhere in the heart provide a “backup” rhythm when the sinus node doesn’t work properly or when impulses are blocked somewhere in the conduction system.\n\nArrhythmias can be caused by:\n\n- A delay or blockage of the electrical signals that control the heartbeat\n- Another part of the heart taking over as pacemaker\n- Changes to heart tissue caused by changes in blood flow, damage to the heart’s electrical system or stiffening or scarring of the heart tissue\n- Excessive exertion, strain or stress\n- An imbalance of fluids, hormones or electrolytes in the blood\n- Certain heart medications\n\nAn arrhythmia occurs when:\n\n- The heart’s natural pacemaker develops an abnormal rate or rhythm.\n- The normal conduction pathway is interrupted or changed.\n- Another part of the heart takes over as a pacemaker.\n***\nLast Reviewed: Sep 24, 2024\n\n[![X formerly known as Twitter](https:\/\/www.heart.org\/en\/-\/media\/Feature\/Navigation\/Social\/x_color.svg?h=54&iar=0&mw=1910&w=54&sc_lang=en)](https:\/\/x.com\/intent\/post?url=https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia) [![Facebook](https:\/\/www.heart.org\/en\/-\/media\/Feature\/Navigation\/Social\/facebook.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](https:\/\/www.facebook.com\/sharer\/sharer.php?u=https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia) [![LinkedIn](https:\/\/www.heart.org\/en\/-\/media\/Feature\/Navigation\/Social\/linkedin.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](https:\/\/www.linkedin.com\/shareArticle?url=https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia) [![Email](https:\/\/www.heart.org\/en\/-\/media\/Feature\/Social\/mail.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](mailto:?subject=What%20is%20an%20Arrhythmia%3F&body=https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia)\n\n![Copy site URL to your clipboard](https:\/\/www.heart.org\/en\/-\/media\/Feature\/Social\/copylink.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)\n\n[![Print](https:\/\/www.heart.org\/en\/-\/media\/Feature\/Social\/print.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia)\n\n[Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia)\n\n[Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia)\n\n- [About Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia)\n  - [Bradycardia: Slow Heart Rate](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/bradycardia--slow-heart-rate)\n  - [Conduction Disorders](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/conduction-disorders)\n  - [Premature Contractions ‒ PACs and PVCs](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/premature-contractions-pacs-and-pvcs)\n  - [Tachycardia: Fast Heart Rate](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/tachycardia--fast-heart-rate)\n  - [Ventricular Fibrillation](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/ventricular-fibrillation)\n  - [Other Heart Rhythm Disorders](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/other-heart-rhythm-disorders)\n  - [Types of Arrhythmia in Children](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/types-of-arrhythmia-in-children)\n- [Understand Your Risk for Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/understand-your-risk-for-arrhythmia)\n- [Symptoms, Diagnosis and Monitoring of Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/symptoms-diagnosis--monitoring-of-arrhythmia)\n  - [Common Tests for Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/symptoms-diagnosis--monitoring-of-arrhythmia\/common-tests-for-arrhythmia)\n  - [Cardiac Event Recorder](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/symptoms-diagnosis--monitoring-of-arrhythmia\/cardiac-event-recorder)\n  - [Electrophysiology Studies](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/symptoms-diagnosis--monitoring-of-arrhythmia\/electrophysiology-studies)\n  - [Holter Monitor](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/symptoms-diagnosis--monitoring-of-arrhythmia\/holter-monitor)\n  - [Syncope (Fainting)](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/symptoms-diagnosis--monitoring-of-arrhythmia\/syncope-fainting)\n  - [Tilt-Table Test](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/symptoms-diagnosis--monitoring-of-arrhythmia\/tilt-table-test)\n- [Prevention and Treatment](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia)\n  - [Medications for Arrhythmia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/medications-for-arrhythmia)\n  - [A Guide to Taking Warfarin](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/a-patients-guide-to-taking-warfarin)\n  - [Ablation for Arrhythmias](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/ablation-for-arrhythmias)\n  - [Cardioversion](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/cardioversion)\n  - [Implantable Cardioverter Defibrillator (ICD)](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/implantable-cardioverter-defibrillator-icd)\n  - [Living With Your ICD](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/living-with-your-icd)\n  - [ICD Questions to Ask Your Doctor](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/questions-to-ask-your-doctor--implantable-cardioverter-defibrillator-icd)\n  - [Pacemaker](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/pacemaker)\n  - [Living With Your Pacemaker](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/living-with-your-pacemaker)\n  - [Devices That May Interfere With ICDs and Pacemakers](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/devices-that-may-interfere-with-icds-and-pacemakers)\n  - [Treating Arrhythmias in Children](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/prevention--treatment-of-arrhythmia\/treating-arrhythmias-in-children)\n- [Arrhythmia Tools and Resources](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/arrhythmia-tools--resources)\n\nRelated Articles\n\n[![Learn about AFib video](https:\/\/www.heart.org\/-\/media\/Images\/Health-Topics\/Video-Thumbnails\/AFib-Learn-about-afib-and-your-heart.jpg?h=422&w=750&sc_lang=en&hash=8C790F9C5FEE262BFB8C92CFE76FBE14) What is Atrial Fibrillation?](https:\/\/www.heart.org\/en\/health-topics\/atrial-fibrillation\/what-is-atrial-fibrillation-afib-or-af)\n\n## Support That Empowers\nRecovery from a heart condition becomes so much more manageable when you have the right kind of emotional support. We’re an online community of patients, survivors and caregivers who know what you’re going through and can help you find your footing on the path to better health.\n\n[Find encouragement](https:\/\/supportnetwork.heart.org\/ \"Find encouragement\")\n\n![graphic of man on laptop with super hero shadow](https:\/\/www.heart.org\/en\/-\/media\/Images\/Health-Topics\/Support-Network\/SuperBoy.jpg?h=480&iar=0&mw=600&w=600&sc_lang=en)\n\nDonate today to help end heart disease and stroke for everyone.\n\n[Donate Now](https:\/\/mygiving.heart.org\/-\/XNPQFTPG \"Donate Now\")\n\n\\*All health\/medical information on this website has been reviewed and approved by the American Heart Association, based on scientific research and American Heart Association guidelines. [Find more information on our content editorial process](https:\/\/www.heart.org\/en\/about-us\/editorial-guidelines).\n\n![American Heart Association](https:\/\/www.heart.org\/en\/-\/media\/Images\/Logos\/Global-Do-No-Edit\/Header\/AHA_Full.svg?h=256&iar=0&mw=1910&w=426&sc_lang=en)\n\n## Contact Us\n**National Center**  \n 7272 Greenville Ave.  \n Dallas, TX 75231\n\n**Customer Service**  \n 1-800-242-8721\n\n[Contact Us](https:\/\/www.heart.org\/en\/about-us\/contact-us)\n\n**Hours**  \n Monday - Friday: 7 a.m. – 7 p.m. CT   \n Saturday: 9 a.m. - 5 p.m. CT  \n Closed on Sundays\n\n**Tax Identification Number** 13-5613797\n\n## About Us\nAbout Us\n\n- [About the American Heart Association](https:\/\/www.heart.org\/en\/about-us \"About the American Heart Association\")\n- [Our Impact](https:\/\/www.heart.org\/en\/impact-map \"Our Impact\")\n- [Annual Report](https:\/\/www.heart.org\/en\/about-us\/2024-2025-annual-report \"Annual Report\")\n- [Financial 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Women](https:\/\/www.goredforwomen.org\/en\/ \"Go Red For Women\")\n- [ShopHeart](https:\/\/www.shopheart.org\/?a=aha-heart.org-bottom-navigation&utm_source=heart.org&utm_medium=referral&utm_campaign=aha-heart.org-bottom-navigation \"ShopHeart\")\n- [ShopCPR](https:\/\/shopcpr.heart.org\/ \"ShopCPR\")\n\n## Our Sites\nOur Sites\n\n- [American Heart Association](https:\/\/www.heart.org\/en\/ \"American Heart Association\")\n- [American Stroke Association](https:\/\/www.stroke.org\/en\/ \"American Stroke Association\")\n- [CPR & ECC](https:\/\/cpr.heart.org\/en\/ \"CPR & ECC\")\n- [Professional Heart Daily](https:\/\/professional.heart.org\/en\/ \"Professional Heart Daily\")\n- [More Sites](https:\/\/www.heart.org\/en\/about-us\/american-heart-association-website-directory \"More Sites\")\n\n- [![Facebook](https:\/\/www.heart.org\/en\/-\/media\/Feature\/Navigation\/Social\/facebook-gray.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](https:\/\/www.facebook.com\/AmericanHeart \"American Heart 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Association](https:\/\/www.heart.org\/en\/-\/media\/Images\/Logos\/Global-Do-No-Edit\/Footer\/Better_Business_Bureau_logo.png?h=60&iar=0&mw=1910&w=45&sc_lang=en)](https:\/\/www.give.org\/charity-reviews\/national\/health\/american-heart-association-in-dallas-tx-173 \"Better Business Bureau Accredited Charity\")\n- [![Charity Navigator Home](https:\/\/www.heart.org\/en\/-\/media\/Images\/Logos\/Global-Do-No-Edit\/Footer\/Charity_Navigator_logo_120.jpg?h=60&iar=0&mw=1910&w=120&sc_lang=en)](https:\/\/www.charitynavigator.org\/ein\/135613797 \"Charity Navigator\")\n- [![Secured by Sectigo page for SSL certificates](https:\/\/www.heart.org\/en\/-\/media\/Images\/Logos\/Global-Do-No-Edit\/Footer\/sectigo_trust_seal_140w.png?h=54&iar=0&mw=1910&w=140&sc_lang=en)](https:\/\/www.sectigo.com\/ssl-certificates-tls \"Secured by Sectigo\")\n\n- [Careers](https:\/\/heart.jobs\/?utm_campaign=heart.org-Footer&vs=2896&utm_medium=Other&utm_source=heart.org-Footer \"Careers\")\n- [Privacy Policy](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/privacy-statement \"Privacy Policy\")\n- [Medical Advice Disclaimer](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/medical-advice \"Medical Advice Disclaimer\")\n- [Accessibility Statement](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/accessibility-statement \"Accessibility Statement\")\n- [Copyright Policy](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/copyright \"Copyright Policy\")\n- [Ethics Policy](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/ethics-policy \"Ethics Policy\")\n- [Conflict of Interest Policy](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/conflict-of-interest-policy \"Conflict of Interest Policy\")\n- [Linking Policy](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/linking-policy \"Linking Policy\")\n- [Whistleblower Policy](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/whistleblower-policy \"Whistleblower Policy\")\n- [Content Editorial Guidelines](https:\/\/www.heart.org\/en\/about-us\/editorial-guidelines \"Content Editorial Guidelines\")\n- [Suppliers & Providers](https:\/\/www.heart.org\/en\/procurement-services-department \"Suppliers & Providers\")\n- [State Fundraising Notices](https:\/\/www.heart.org\/en\/about-us\/statements-and-policies\/state-fundraising-notices \"State Fundraising Notices\")\n\nCookie Settings\n\n©2026 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited.  \n The American Heart Association is a qualified 501(c)(3) tax-exempt organization.   \n \\*Red Dress ™ DHHS, Go Red ™ AHA ; National Wear Red Day® is a registered trademark.\n\n## Speed Bump\n×\n\n![American Heart Association logo](https:\/\/www.heart.org\/-\/media\/Images\/Logos\/Global-Do-No-Edit\/Two-Click\/ahalogo.png?h=165&w=280&sc_lang=en&hash=E4F07F7A44585F05A690B33CEC7B6E8D)\n\nThis link is provided for convenience only and is not an endorsement of either the linked-to entity or any product or service.\n\n[Proceed]()","attrs_readable_markdown":"![couple on a beach](https:\/\/www.heart.org\/-\/media\/Images\/Health-Topics\/Arrhythmia\/couples-piggybacking-at-beach.jpg?sc_lang=en)\n\nThe term “arrhythmia” refers to any problem in the rate or rhythm of a person’s heartbeat. During an arrhythmia, the electrical impulses may be too fast, too slow or erratic, causing an irregular heartbeat.\n\nWhen the heart doesn’t beat properly, it can’t pump blood effectively. When this happens, the lungs, brain and all other organs can’t work properly and may shut down or be damaged. [View an animation of arrhythmia](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=arrhyt).\n\n[![arrhythmia](https:\/\/www.heart.org\/-\/media\/Images\/Health-Topics\/Arrhythmia\/Arrhythmias.jpg?sc_lang=en)](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=arrhyt)\n\n## Types of Arrhythmias\n- **[Atrial Fibrillation](https:\/\/www.heart.org\/en\/health-topics\/atrial-fibrillation)**\n- **[Atrial Flutter](https:\/\/www.heart.org\/en\/health-topics\/atrial-fibrillation\/what-is-atrial-fibrillation-afib-or-af\/atrial-flutter)**\n- **[Bradycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/bradycardia--slow-heart-rate)**\n- **[Conduction Disorders](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/conduction-disorders)**\n- **[Premature Contraction](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/premature-contractions-pacs-and-pvcs)**\n- **[Tachycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/tachycardia--fast-heart-rate)**\n- **[Ventricular Fibrillation](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/ventricular-fibrillation)**\n- [**Other Rhythm Disorders**](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/other-heart-rhythm-disorders)\n- [**Types of Arrhythmias in Children**](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/types-of-arrhythmia-in-children)\n\nThe normal heart is a strong, muscular pump about the size of a fist. It pumps blood to all parts of the body.\n\n## To understand how the heart pumps, learn about: Structure of the heart\n[![Heart valve anatomy animation](https:\/\/www.heart.org\/-\/media\/Images\/Health-Topics\/Watch-Learn-and-Live\/Valve-anatomy.jpg?sc_lang=en)](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=anatom)\n\n[Watch an animation of heart valve anatomy](http:\/\/watchlearnlive.heart.org\/CVML_Player.php?moduleSelect=anatom)\n\n### The heart: Four chambers, four valves\nThe heart has four chambers, two on the right and two on the left:\n\n- Two upper chambers are called atria (one is called an atrium).\n- Two lower chambers are called ventricles.\n\nThe heart also has four valves that open and close to let blood flow in only one direction when the heart contracts (beats). The four heart valves are:\n\n- Tricuspid valve, located between the right atrium and right ventricle\n- Pulmonary or pulmonic valve, between the right ventricle and the pulmonary artery\n- Mitral valve, between the left atrium and left ventricle\n- Aortic valve, between the left ventricle and the aorta\n\nEach valve has a set of flaps (also called leaflets or cusps). The mitral valve has two flaps; the others have three. Blood flow occurs only when there’s a difference in pressure across the valves, which causes them to open. Under normal conditions, the valves allow blood to flow in only one direction.\n\nThe heart pumps blood to the lungs and to all the body’s tissues by a sequence of highly organized contractions of the four chambers. For the heart to function properly, the four chambers must beat in an organized way.\n\n## Electrical system of the heart\n### Electrical signals control the pump\nThe heartbeat (contraction) begins when an electrical impulse from the sinus node (also called SA node) moves through the heart’s muscle tissue. The SA node is sometimes called the heart’s “natural pacemaker” because it starts the impulses for the heartbeat.\n\nThe normal electrical sequence begins in the right atrium and spreads throughout the atria to the atrioventricular (AV) node. Electrical impulses travel down the bundle of His from the AV node and through the Purkinje fibers, causing the ventricles to contract.\n\nThe normal heart beats in a regular manner because electrical impulses cause a sequence of organized contractions. In an adult, a normal heart beats 60 to 100 times a minute.\n\n[Electrocardiography (ECG or EKG)](https:\/\/www.heart.org\/en\/health-topics\/heart-attack\/diagnosing-a-heart-attack\/electrocardiogram) is a simple, painless test that records the heart’s electrical activity and can help detect arrhythmias (abnormal heart rhythms).\n\n### Abnormal heart rhythms (arrhythmias)\nArrhythmias are abnormal heartbeats. The term “arrhythmia” refers to any change from the normal sequence of electrical impulses.\n\nSome arrhythmias are so brief (such as a temporary pause or premature beat) that the overall heart rate or rhythm isn’t greatly affected. But if arrhythmias last longer, they may make the heart rate too slow, too fast or erratic, so the heart pumps less effectively.\n\n- A fast heart rate (in adults, more than 100 beats per minute) is called [tachycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/tachycardia--fast-heart-rate).\n- A slow heart rate (less than 60 beats per minute) is called [bradycardia](https:\/\/www.heart.org\/en\/health-topics\/arrhythmia\/about-arrhythmia\/bradycardia--slow-heart-rate).\n#### ***Causes***\nNormally, the heart’s most rapidly firing cells are in the sinus node, making that area a natural pacemaker. Under some conditions, almost all heart tissue can start an impulse of the type that can generate a heartbeat.\n\n- Cells in the heart’s conduction system can fire automatically and start electrical activity. This activity can interrupt the normal order of the heart’s pumping activity.\n- Secondary pacemakers elsewhere in the heart provide a “backup” rhythm when the sinus node doesn’t work properly or when impulses are blocked somewhere in the conduction system.\n\nArrhythmias can be caused by:\n\n- A delay or blockage of the electrical signals that control the heartbeat\n- Another part of the heart taking over as pacemaker\n- Changes to heart tissue caused by changes in blood flow, damage to the heart’s electrical system or stiffening or scarring of the heart tissue\n- Excessive exertion, strain or stress\n- An imbalance of fluids, hormones or electrolytes in the blood\n- Certain heart medications\n\nAn arrhythmia occurs when:\n\n- The heart’s natural pacemaker develops an abnormal rate or rhythm.\n- The normal conduction pathway is interrupted or changed.\n- Another part of the heart takes over as a pacemaker.","meta_canonical":null}

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URL	https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia
Last Crawled	2026-04-09 10:24:29 (9 days ago)
First Indexed	2018-07-31 05:51:49 (7 years ago)
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Meta Title	What is an Arrhythmia? \| American Heart Association
Meta Description	What is an arrhythmia? The American Heart Association explains that arrhythmia refers to any problem in the rate and/or rhythm of a person’s heartbeat, such as atrial fibrillation, bradycardia, tachycardia, conduction disorders, rhythm disorders, ventricular fibrillation, premature contractions and more.
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Boilerpipe Text	The term “arrhythmia” refers to any problem in the rate or rhythm of a person’s heartbeat. During an arrhythmia, the electrical impulses may be too fast, too slow or erratic, causing an irregular heartbeat. When the heart doesn’t beat properly, it can’t pump blood effectively. When this happens, the lungs, brain and all other organs can’t work properly and may shut down or be damaged. View an animation of arrhythmia . Types of Arrhythmias Atrial Fibrillation Atrial Flutter Bradycardia Conduction Disorders Premature Contraction Tachycardia Ventricular Fibrillation Other Rhythm Disorders Types of Arrhythmias in Children The normal heart is a strong, muscular pump about the size of a fist. It pumps blood to all parts of the body. To understand how the heart pumps, learn about: Structure of the heart Watch an animation of heart valve anatomy The heart: Four chambers, four valves The heart has four chambers, two on the right and two on the left: Two upper chambers are called atria (one is called an atrium). Two lower chambers are called ventricles. The heart also has four valves that open and close to let blood flow in only one direction when the heart contracts (beats). The four heart valves are: Tricuspid valve, located between the right atrium and right ventricle Pulmonary or pulmonic valve, between the right ventricle and the pulmonary artery Mitral valve, between the left atrium and left ventricle Aortic valve, between the left ventricle and the aorta Each valve has a set of flaps (also called leaflets or cusps). The mitral valve has two flaps; the others have three. Blood flow occurs only when there’s a difference in pressure across the valves, which causes them to open. Under normal conditions, the valves allow blood to flow in only one direction. The heart pumps blood to the lungs and to all the body’s tissues by a sequence of highly organized contractions of the four chambers. For the heart to function properly, the four chambers must beat in an organized way. Electrical system of the heart Electrical signals control the pump The heartbeat (contraction) begins when an electrical impulse from the sinus node (also called SA node) moves through the heart’s muscle tissue. The SA node is sometimes called the heart’s “natural pacemaker” because it starts the impulses for the heartbeat. The normal electrical sequence begins in the right atrium and spreads throughout the atria to the atrioventricular (AV) node. Electrical impulses travel down the bundle of His from the AV node and through the Purkinje fibers, causing the ventricles to contract. The normal heart beats in a regular manner because electrical impulses cause a sequence of organized contractions. In an adult, a normal heart beats 60 to 100 times a minute. Electrocardiography (ECG or EKG) is a simple, painless test that records the heart’s electrical activity and can help detect arrhythmias (abnormal heart rhythms). Abnormal heart rhythms (arrhythmias) Arrhythmias are abnormal heartbeats. The term “arrhythmia” refers to any change from the normal sequence of electrical impulses. Some arrhythmias are so brief (such as a temporary pause or premature beat) that the overall heart rate or rhythm isn’t greatly affected. But if arrhythmias last longer, they may make the heart rate too slow, too fast or erratic, so the heart pumps less effectively. A fast heart rate (in adults, more than 100 beats per minute) is called tachycardia . A slow heart rate (less than 60 beats per minute) is called bradycardia . Causes Normally, the heart’s most rapidly firing cells are in the sinus node, making that area a natural pacemaker. Under some conditions, almost all heart tissue can start an impulse of the type that can generate a heartbeat. Cells in the heart’s conduction system can fire automatically and start electrical activity. This activity can interrupt the normal order of the heart’s pumping activity. Secondary pacemakers elsewhere in the heart provide a “backup” rhythm when the sinus node doesn’t work properly or when impulses are blocked somewhere in the conduction system. Arrhythmias can be caused by: A delay or blockage of the electrical signals that control the heartbeat Another part of the heart taking over as pacemaker Changes to heart tissue caused by changes in blood flow, damage to the heart’s electrical system or stiffening or scarring of the heart tissue Excessive exertion, strain or stress An imbalance of fluids, hormones or electrolytes in the blood Certain heart medications An arrhythmia occurs when: The heart’s natural pacemaker develops an abnormal rate or rhythm. The normal conduction pathway is interrupted or changed. Another part of the heart takes over as a pacemaker.
Markdown	[Skip to main content](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia#main-content) - [Heart Attack and Stroke Symptoms](https://www.heart.org/en/about-us/heart-attack-and-stroke-symptoms) - [Volunteer](https://www.heart.org/en/volunteer) - [Learn CPR](https://cpr.heart.org/en/) - [ShopHeart](https://www.shopheart.org/?utm_source=heart.org&utm_medium=Referral&utm_campaign=AHA-Parent-Site-Top-Nav-Desktop) Menu Close Menu - Healthy Living - [Healthy Living](https://www.heart.org/en/healthy-living) - [Healthy Eating](https://www.heart.org/en/healthy-living/healthy-eating) - [Add Color](https://www.heart.org/en/healthy-living/healthy-eating/add-color) - [Cooking Skills](https://www.heart.org/en/healthy-living/healthy-eating/cooking-skills) - [Eat Smart](https://www.heart.org/en/healthy-living/healthy-eating/eat-smart) - [Healthy Food Facts](https://www.heart.org/en/healthy-living/healthy-eating/healthy-food-facts) - [Heart-Check Foods](https://www.heart.org/en/healthy-living/healthy-eating/heart-check-foods) - 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[Atrial Fibrillation](https://www.heart.org/en/health-topics/atrial-fibrillation) - [Cardiac Arrest](https://www.heart.org/en/health-topics/cardiac-arrest) - [Cardiac Rehab](https://www.heart.org/en/health-topics/cardiac-rehab) - [Cardiomyopathy](https://www.heart.org/en/health-topics/cardiomyopathy) - [Cardiovascular-Kidney-Metabolic](https://www.heart.org/en/health-topics/cardiovascular-kidney-metabolic-syndrome) - [Cholesterol](https://www.heart.org/en/health-topics/cholesterol) - [Congenital Heart Disease](https://www.heart.org/en/health-topics/congenital-heart-defects) - [Diabetes](https://www.heart.org/en/health-topics/diabetes) - [Flu Prevention](https://www.heart.org/en/health-topics/flu-prevention) - [Heart Attack](https://www.heart.org/en/health-topics/heart-attack) - [Heart Failure](https://www.heart.org/en/health-topics/heart-failure) - [Heart Murmurs](https://www.heart.org/en/health-topics/heart-murmurs) - [Heart Valve Disease](https://www.heart.org/en/health-topics/heart-valve-problems-and-disease) - 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[Patient and Caregiver Support](https://www.heart.org/en/health-topics/consumer-healthcare) - [Support Network Community](https://supportnetwork.heart.org/) - [Telehealth Resources](https://www.heart.org/en/professional/telehealth/telehealth-patient-resources) - Professionals - [Professional Resources](https://www.heart.org/en/professional) - [Professional Heart Daily](https://professional.heart.org/en/) - [Communities]() - [Education](https://professional.heart.org/en/education) - [Guidelines & Statements](https://professional.heart.org/en/guidelines-and-statements) - [Journals](https://professional.heart.org/en/journals) - [Meetings](https://professional.heart.org/en/meetings) - [Professional Membership](https://professional.heart.org/en/professional-membership/become-a-member) - [Research](https://professional.heart.org/en/research-programs) - [Science News](https://professional.heart.org/en/science-news) - [Quality Improvement](https://www.heart.org/en/professional/quality-improvement) - 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[Target: Aortic Stenosis™](https://www.heart.org/en/professional/quality-improvement/target-aortic-stenosis "Target: Aortic Stenosis® ") - [Target: Heart Failure℠](https://www.heart.org/en/professional/quality-improvement/target-heart-failure) - [Target: Stroke℠](https://www.heart.org/en/professional/quality-improvement/target-stroke) - [Educators](https://www.heart.org/en/professional/educator) - [Kids Health Initiatives](https://www.heart.org/en/professional/educator/kids-health-initiatives "Kids Health Initiatives ") - [NFL PLAY 60](https://www.heart.org/en/professional/educator/nfl-play-60) - [School Programs](https://www.heart.org/en/professional/educator/school-programs) - [Teaching Gardens](https://www.heart.org/en/professional/educator/teaching-gardens) - [Data Science](https://www.heart.org/en/professional/datascience) - [Health Care by Food™](https://healthcarexfood.org/) - [Million Hearts Collaboration®](https://www.heart.org/en/professional/million-hearts) - Get Involved - 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[Atrial Fibrillation](https://www.heart.org/en/health-topics/atrial-fibrillation) - [Cardiac Arrest](https://www.heart.org/en/health-topics/cardiac-arrest) - [Cardiac Rehab](https://www.heart.org/en/health-topics/cardiac-rehab) - [Cardiomyopathy](https://www.heart.org/en/health-topics/cardiomyopathy) - [Cardiovascular-Kidney-Metabolic](https://www.heart.org/en/health-topics/cardiovascular-kidney-metabolic-syndrome) - [Cholesterol](https://www.heart.org/en/health-topics/cholesterol) - [Congenital Heart Disease](https://www.heart.org/en/health-topics/congenital-heart-defects) - [Diabetes](https://www.heart.org/en/health-topics/diabetes) - [Flu Prevention](https://www.heart.org/en/health-topics/flu-prevention) - [Heart Attack](https://www.heart.org/en/health-topics/heart-attack) - [Heart Failure](https://www.heart.org/en/health-topics/heart-failure) - [Heart Murmurs](https://www.heart.org/en/health-topics/heart-murmurs) - [Heart Valve Disease](https://www.heart.org/en/health-topics/heart-valve-problems-and-disease) - [High Blood Pressure](https://www.heart.org/en/health-topics/high-blood-pressure) - [Infective Endocarditis](https://www.heart.org/en/health-topics/infective-endocarditis) - [Kawasaki Disease](https://www.heart.org/en/health-topics/kawasaki-disease) - [Metabolic Syndrome](https://www.heart.org/en/health-topics/metabolic-syndrome) - [Myocarditis](https://www.heart.org/en/health-topics/myocarditis) - [Oral Health](https://www.heart.org/en/health-topics/oral-health) - [Pericarditis](https://www.heart.org/en/health-topics/pericarditis) - [Peripheral Artery Disease](https://www.heart.org/en/health-topics/peripheral-artery-disease) - [Pulmonary Embolism](https://www.heart.org/en/health-topics/pulmonary-embolism) - [Sleep Disorders](https://www.heart.org/en/health-topics/sleep-disorders) - [Stroke](https://www.stroke.org/en/) - [Venous Thromboembolism](https://www.heart.org/en/health-topics/venous-thromboembolism) - [Weight and Obesity](https://www.heart.org/en/health-topics/weight-and-obesity) - - [Patient and Caregiver Support](https://www.heart.org/en/health-topics/consumer-healthcare) - [Support Network Community](https://supportnetwork.heart.org/) - [Telehealth Resources](https://www.heart.org/en/professional/telehealth/telehealth-patient-resources) - Professionals [Professional Resources](https://www.heart.org/en/professional) - Get Involved [Get Involved](https://www.heart.org/en/get-involved) - Ways to Give [Ways to Give](https://www.heart.org/en/get-involved/ways-to-give) - - [American Heart Challenge](https://www2.heart.org/site/SPageNavigator/ahc_resources_search.html) - [Cor Vitae Society](https://www.heart.org/en/get-involved/ways-to-give/cor-vitae-society) - [Create a Tribute Page](https://ahatribute.funraise.org/) - [Donor Advised Fund](https://www.heart.org/en/get-involved/ways-to-give/planned-giving/ways-to-give-now/donor-advised-fund) - [Fundraising Events](https://www.heart.org/en/get-involved/ways-to-give/for-companies/fundraising-events) - [Gifts of Stock and Mutual Funds](https://www.heart.org/en/get-involved/ways-to-give/planned-giving/ways-to-give-now/stock-gifts-and-mutual-funds) - [Heritage Brick Walk](https://www.heart.org/en/get-involved/ways-to-give/heritage-brick-walk) - [Honor a Loved One](https://mygiving.heart.org/-/XCBTSYZR "Honor a Loved One") - [Kids Heart Challenge](https://www2.heart.org/site/SPageNavigator/khc_resources_search.html) - [Make a Crypto Gift](https://www.heart.org/en/get-involved/ways-to-give/cryptocurrency) - [Make a Memorial Gift](https://mygiving.heart.org/-/XTPMHHQM "Memorial Gifts") - [Monthly Giving As Seen On TV](https://www.heart.org/en/get-involved/ways-to-give/monthly-giving-saves-lives "Monthly Giving Saves Lives") - [Paul Dudley White Legacy Circle](https://www.heart.org/en/get-involved/ways-to-give/planned-giving/paul-dudley-white-legacy-circle) - [Planned Giving](https://www.heart.org/en/get-involved/ways-to-give/planned-giving) - [Raise Your Way](https://raiseyourwayforaha.funraise.org/) - [Retail Supporters](https://www.heart.org/en/get-involved/ways-to-give/life-is-why) - [Social Impact Funds](https://www.heart.org/en/get-involved/ways-to-give/social-impact-fund) - [Wills and Trusts](https://www.heart.org/en/get-involved/ways-to-give/planned-giving/ways-to-leave-a-legacy/wills-and-trusts) - - [Donate Once](https://mygiving.heart.org/-/XMNFTTTW) - [Donate Monthly](https://pages.heart.org/drtv_helpheart?s_subsrc=site_nav) - About Us - Learn CPR [CPR and First Aid](https://cpr.heart.org/en/) - In Your Community - [Heart Attack and Stroke Symptoms](https://www.heart.org/en/about-us/heart-attack-and-stroke-symptoms) - [Learn CPR](https://cpr.heart.org/en/) - [Volunteer](https://www.heart.org/en/volunteer) - [ShopHeart](https://www.shopheart.org/?utm_source=heart.org&utm_medium=Referral&utm_campaign=AHA-Parent-Site-Top-Nav-Mobile) 1. [Home](https://www.heart.org/en/) 2. [Health Topics](https://www.heart.org/en/health-topics) 3. [Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia) 4. [About Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia) # What is an Arrhythmia? ![couple on a beach](https://www.heart.org/-/media/Images/Health-Topics/Arrhythmia/couples-piggybacking-at-beach.jpg?sc_lang=en) The term “arrhythmia” refers to any problem in the rate or rhythm of a person’s heartbeat. During an arrhythmia, the electrical impulses may be too fast, too slow or erratic, causing an irregular heartbeat. When the heart doesn’t beat properly, it can’t pump blood effectively. When this happens, the lungs, brain and all other organs can’t work properly and may shut down or be damaged. [View an animation of arrhythmia](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=arrhyt). [![arrhythmia](https://www.heart.org/-/media/Images/Health-Topics/Arrhythmia/Arrhythmias.jpg?sc_lang=en)](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=arrhyt) ## Types of Arrhythmias - [Atrial Fibrillation](https://www.heart.org/en/health-topics/atrial-fibrillation) - [Atrial Flutter](https://www.heart.org/en/health-topics/atrial-fibrillation/what-is-atrial-fibrillation-afib-or-af/atrial-flutter) - [Bradycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate) - [Conduction Disorders](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/conduction-disorders) - [Premature Contraction](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/premature-contractions-pacs-and-pvcs) - [Tachycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate) - [Ventricular Fibrillation](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/ventricular-fibrillation) - [Other Rhythm Disorders](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/other-heart-rhythm-disorders) - [Types of Arrhythmias in Children](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/types-of-arrhythmia-in-children) The normal heart is a strong, muscular pump about the size of a fist. It pumps blood to all parts of the body. ## To understand how the heart pumps, learn about: Structure of the heart [![Heart valve anatomy animation](https://www.heart.org/-/media/Images/Health-Topics/Watch-Learn-and-Live/Valve-anatomy.jpg?sc_lang=en)](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=anatom) [Watch an animation of heart valve anatomy](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=anatom) ### The heart: Four chambers, four valves The heart has four chambers, two on the right and two on the left: - Two upper chambers are called atria (one is called an atrium). - Two lower chambers are called ventricles. The heart also has four valves that open and close to let blood flow in only one direction when the heart contracts (beats). The four heart valves are: - Tricuspid valve, located between the right atrium and right ventricle - Pulmonary or pulmonic valve, between the right ventricle and the pulmonary artery - Mitral valve, between the left atrium and left ventricle - Aortic valve, between the left ventricle and the aorta Each valve has a set of flaps (also called leaflets or cusps). The mitral valve has two flaps; the others have three. Blood flow occurs only when there’s a difference in pressure across the valves, which causes them to open. Under normal conditions, the valves allow blood to flow in only one direction. The heart pumps blood to the lungs and to all the body’s tissues by a sequence of highly organized contractions of the four chambers. For the heart to function properly, the four chambers must beat in an organized way. ## Electrical system of the heart ### Electrical signals control the pump The heartbeat (contraction) begins when an electrical impulse from the sinus node (also called SA node) moves through the heart’s muscle tissue. The SA node is sometimes called the heart’s “natural pacemaker” because it starts the impulses for the heartbeat. The normal electrical sequence begins in the right atrium and spreads throughout the atria to the atrioventricular (AV) node. Electrical impulses travel down the bundle of His from the AV node and through the Purkinje fibers, causing the ventricles to contract. The normal heart beats in a regular manner because electrical impulses cause a sequence of organized contractions. In an adult, a normal heart beats 60 to 100 times a minute. [Electrocardiography (ECG or EKG)](https://www.heart.org/en/health-topics/heart-attack/diagnosing-a-heart-attack/electrocardiogram) is a simple, painless test that records the heart’s electrical activity and can help detect arrhythmias (abnormal heart rhythms). ### Abnormal heart rhythms (arrhythmias) Arrhythmias are abnormal heartbeats. The term “arrhythmia” refers to any change from the normal sequence of electrical impulses. Some arrhythmias are so brief (such as a temporary pause or premature beat) that the overall heart rate or rhythm isn’t greatly affected. But if arrhythmias last longer, they may make the heart rate too slow, too fast or erratic, so the heart pumps less effectively. - A fast heart rate (in adults, more than 100 beats per minute) is called [tachycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate). - A slow heart rate (less than 60 beats per minute) is called [bradycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate). #### *Causes* Normally, the heart’s most rapidly firing cells are in the sinus node, making that area a natural pacemaker. Under some conditions, almost all heart tissue can start an impulse of the type that can generate a heartbeat. - Cells in the heart’s conduction system can fire automatically and start electrical activity. This activity can interrupt the normal order of the heart’s pumping activity. - Secondary pacemakers elsewhere in the heart provide a “backup” rhythm when the sinus node doesn’t work properly or when impulses are blocked somewhere in the conduction system. Arrhythmias can be caused by: - A delay or blockage of the electrical signals that control the heartbeat - Another part of the heart taking over as pacemaker - Changes to heart tissue caused by changes in blood flow, damage to the heart’s electrical system or stiffening or scarring of the heart tissue - Excessive exertion, strain or stress - An imbalance of fluids, hormones or electrolytes in the blood - Certain heart medications An arrhythmia occurs when: - The heart’s natural pacemaker develops an abnormal rate or rhythm. - The normal conduction pathway is interrupted or changed. - Another part of the heart takes over as a pacemaker. *** Last Reviewed: Sep 24, 2024 [![X formerly known as Twitter](https://www.heart.org/en/-/media/Feature/Navigation/Social/x_color.svg?h=54&iar=0&mw=1910&w=54&sc_lang=en)](https://x.com/intent/post?url=https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia) [![Facebook](https://www.heart.org/en/-/media/Feature/Navigation/Social/facebook.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](https://www.facebook.com/sharer/sharer.php?u=https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia) [![LinkedIn](https://www.heart.org/en/-/media/Feature/Navigation/Social/linkedin.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](https://www.linkedin.com/shareArticle?url=https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia) [![Email](https://www.heart.org/en/-/media/Feature/Social/mail.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](mailto:?subject=What%20is%20an%20Arrhythmia%3F&body=https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia) ![Copy site URL to your clipboard](https://www.heart.org/en/-/media/Feature/Social/copylink.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en) [![Print](https://www.heart.org/en/-/media/Feature/Social/print.svg?h=52&iar=0&mw=1910&w=52&sc_lang=en)](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia) [Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia) [Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia) - [About Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia) - [Bradycardia: Slow Heart Rate](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate) - [Conduction Disorders](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/conduction-disorders) - [Premature Contractions ‒ PACs and PVCs](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/premature-contractions-pacs-and-pvcs) - [Tachycardia: Fast Heart Rate](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate) - [Ventricular Fibrillation](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/ventricular-fibrillation) - [Other Heart Rhythm Disorders](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/other-heart-rhythm-disorders) - [Types of Arrhythmia in Children](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/types-of-arrhythmia-in-children) - [Understand Your Risk for Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia/understand-your-risk-for-arrhythmia) - [Symptoms, Diagnosis and Monitoring of Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis--monitoring-of-arrhythmia) - [Common Tests for Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis--monitoring-of-arrhythmia/common-tests-for-arrhythmia) - [Cardiac Event Recorder](https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis--monitoring-of-arrhythmia/cardiac-event-recorder) - [Electrophysiology Studies](https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis--monitoring-of-arrhythmia/electrophysiology-studies) - [Holter Monitor](https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis--monitoring-of-arrhythmia/holter-monitor) - [Syncope (Fainting)](https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis--monitoring-of-arrhythmia/syncope-fainting) - [Tilt-Table Test](https://www.heart.org/en/health-topics/arrhythmia/symptoms-diagnosis--monitoring-of-arrhythmia/tilt-table-test) - [Prevention and Treatment](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia) - [Medications for Arrhythmia](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/medications-for-arrhythmia) - [A Guide to Taking Warfarin](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/a-patients-guide-to-taking-warfarin) - [Ablation for Arrhythmias](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/ablation-for-arrhythmias) - [Cardioversion](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/cardioversion) - [Implantable Cardioverter Defibrillator (ICD)](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/implantable-cardioverter-defibrillator-icd) - [Living With Your ICD](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/living-with-your-icd) - [ICD Questions to Ask Your Doctor](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/questions-to-ask-your-doctor--implantable-cardioverter-defibrillator-icd) - [Pacemaker](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/pacemaker) - [Living With Your Pacemaker](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/living-with-your-pacemaker) - [Devices That May Interfere With ICDs and Pacemakers](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/devices-that-may-interfere-with-icds-and-pacemakers) - [Treating Arrhythmias in Children](https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/treating-arrhythmias-in-children) - [Arrhythmia Tools and Resources](https://www.heart.org/en/health-topics/arrhythmia/arrhythmia-tools--resources) Related Articles [![Learn about AFib video](https://www.heart.org/-/media/Images/Health-Topics/Video-Thumbnails/AFib-Learn-about-afib-and-your-heart.jpg?h=422&w=750&sc_lang=en&hash=8C790F9C5FEE262BFB8C92CFE76FBE14) What is Atrial Fibrillation?](https://www.heart.org/en/health-topics/atrial-fibrillation/what-is-atrial-fibrillation-afib-or-af) ## Support That Empowers Recovery from a heart condition becomes so much more manageable when you have the right kind of emotional support. 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Readable Markdown	![couple on a beach](https://www.heart.org/-/media/Images/Health-Topics/Arrhythmia/couples-piggybacking-at-beach.jpg?sc_lang=en) The term “arrhythmia” refers to any problem in the rate or rhythm of a person’s heartbeat. During an arrhythmia, the electrical impulses may be too fast, too slow or erratic, causing an irregular heartbeat. When the heart doesn’t beat properly, it can’t pump blood effectively. When this happens, the lungs, brain and all other organs can’t work properly and may shut down or be damaged. [View an animation of arrhythmia](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=arrhyt). [![arrhythmia](https://www.heart.org/-/media/Images/Health-Topics/Arrhythmia/Arrhythmias.jpg?sc_lang=en)](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=arrhyt) ## Types of Arrhythmias - [Atrial Fibrillation](https://www.heart.org/en/health-topics/atrial-fibrillation) - [Atrial Flutter](https://www.heart.org/en/health-topics/atrial-fibrillation/what-is-atrial-fibrillation-afib-or-af/atrial-flutter) - [Bradycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate) - [Conduction Disorders](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/conduction-disorders) - [Premature Contraction](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/premature-contractions-pacs-and-pvcs) - [Tachycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate) - [Ventricular Fibrillation](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/ventricular-fibrillation) - [Other Rhythm Disorders](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/other-heart-rhythm-disorders) - [Types of Arrhythmias in Children](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/types-of-arrhythmia-in-children) The normal heart is a strong, muscular pump about the size of a fist. It pumps blood to all parts of the body. ## To understand how the heart pumps, learn about: Structure of the heart [![Heart valve anatomy animation](https://www.heart.org/-/media/Images/Health-Topics/Watch-Learn-and-Live/Valve-anatomy.jpg?sc_lang=en)](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=anatom) [Watch an animation of heart valve anatomy](http://watchlearnlive.heart.org/CVML_Player.php?moduleSelect=anatom) ### The heart: Four chambers, four valves The heart has four chambers, two on the right and two on the left: - Two upper chambers are called atria (one is called an atrium). - Two lower chambers are called ventricles. The heart also has four valves that open and close to let blood flow in only one direction when the heart contracts (beats). The four heart valves are: - Tricuspid valve, located between the right atrium and right ventricle - Pulmonary or pulmonic valve, between the right ventricle and the pulmonary artery - Mitral valve, between the left atrium and left ventricle - Aortic valve, between the left ventricle and the aorta Each valve has a set of flaps (also called leaflets or cusps). The mitral valve has two flaps; the others have three. Blood flow occurs only when there’s a difference in pressure across the valves, which causes them to open. Under normal conditions, the valves allow blood to flow in only one direction. The heart pumps blood to the lungs and to all the body’s tissues by a sequence of highly organized contractions of the four chambers. For the heart to function properly, the four chambers must beat in an organized way. ## Electrical system of the heart ### Electrical signals control the pump The heartbeat (contraction) begins when an electrical impulse from the sinus node (also called SA node) moves through the heart’s muscle tissue. The SA node is sometimes called the heart’s “natural pacemaker” because it starts the impulses for the heartbeat. The normal electrical sequence begins in the right atrium and spreads throughout the atria to the atrioventricular (AV) node. Electrical impulses travel down the bundle of His from the AV node and through the Purkinje fibers, causing the ventricles to contract. The normal heart beats in a regular manner because electrical impulses cause a sequence of organized contractions. In an adult, a normal heart beats 60 to 100 times a minute. [Electrocardiography (ECG or EKG)](https://www.heart.org/en/health-topics/heart-attack/diagnosing-a-heart-attack/electrocardiogram) is a simple, painless test that records the heart’s electrical activity and can help detect arrhythmias (abnormal heart rhythms). ### Abnormal heart rhythms (arrhythmias) Arrhythmias are abnormal heartbeats. The term “arrhythmia” refers to any change from the normal sequence of electrical impulses. Some arrhythmias are so brief (such as a temporary pause or premature beat) that the overall heart rate or rhythm isn’t greatly affected. But if arrhythmias last longer, they may make the heart rate too slow, too fast or erratic, so the heart pumps less effectively. - A fast heart rate (in adults, more than 100 beats per minute) is called [tachycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/tachycardia--fast-heart-rate). - A slow heart rate (less than 60 beats per minute) is called [bradycardia](https://www.heart.org/en/health-topics/arrhythmia/about-arrhythmia/bradycardia--slow-heart-rate). #### *Causes* Normally, the heart’s most rapidly firing cells are in the sinus node, making that area a natural pacemaker. Under some conditions, almost all heart tissue can start an impulse of the type that can generate a heartbeat. - Cells in the heart’s conduction system can fire automatically and start electrical activity. This activity can interrupt the normal order of the heart’s pumping activity. - Secondary pacemakers elsewhere in the heart provide a “backup” rhythm when the sinus node doesn’t work properly or when impulses are blocked somewhere in the conduction system. Arrhythmias can be caused by: - A delay or blockage of the electrical signals that control the heartbeat - Another part of the heart taking over as pacemaker - Changes to heart tissue caused by changes in blood flow, damage to the heart’s electrical system or stiffening or scarring of the heart tissue - Excessive exertion, strain or stress - An imbalance of fluids, hormones or electrolytes in the blood - Certain heart medications An arrhythmia occurs when: - The heart’s natural pacemaker develops an abnormal rate or rhythm. - The normal conduction pathway is interrupted or changed. - Another part of the heart takes over as a pacemaker.
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