Atrial fibrillation or flutter
Auricular fibrillation; A-fib; AfibAtrial fibrillation or flutter is a common type of abnormal heartbeat. The heart rhythm is fast and most often irregular.
Causes
When working well, the 4 chambers of the heart contract (squeeze) in an organized way.
Electrical signals direct your heart to pump the right amount of blood for your body's needs. The signals begin in an area called the sinoatrial node (also called the sinus node or SA node).
In people with atrial fibrillation, the electrical impulse of the heart is not regular. This is because the sinoatrial node no longer controls the heart rhythm.
- Parts of the heart cannot contract in an organized pattern.
- As a result, the heart cannot pump enough blood to meet the body's needs.
In people with atrial flutter, the ventricles (lower heart chambers) may beat very rapidly, but in a regular pattern.
These problems can affect both men and women. They become more common with increasing age.
Common causes of atrial fibrillation include:
- Alcohol use (especially binge drinking)
- Coronary artery disease
Coronary artery disease
Coronary heart disease is a narrowing of the small blood vessels that supply blood and oxygen to the heart. Coronary heart disease (CHD) is also cal...
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Heart attack
Most heart attacks are caused by a blood clot that blocks one of the coronary arteries. The coronary arteries bring blood and oxygen to the heart. ...
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Heart bypass surgery creates a new route, called a bypass, for blood and oxygen to go around a blockage to reach your heart.
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Heart failure
Heart failure is a condition in which the heart is no longer able to pump oxygen-rich blood to the rest of the body efficiently. This causes symptom...
ImageRead Article Now Book Mark ArticleEnlarged heart
Cardiomyopathy is disease in which the heart muscle becomes weakened, stretched, or has another structural problem. It often contributes to the hear...
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- Hypertension
Hypertension
Blood pressure is a measurement of the force exerted against the walls of your arteries as your heart pumps blood to your body. Hypertension is the ...
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- Overactive thyroid gland (hyperthyroidism)
Hyperthyroidism
Hyperthyroidism is a condition in which the thyroid gland makes too much thyroid hormone. The condition is often called overactive thyroid.
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Pericarditis
Pericarditis is a condition in which the sac-like covering around the heart (pericardium) becomes inflamed.
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Sick sinus syndrome
Normally, the heartbeat starts in an area in the top chambers of the heart (atria). This area is the heart's pacemaker. It is called the sinoatrial...
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Symptoms
You may not be aware that your heart is not beating in a normal pattern.
Symptoms may start or stop suddenly. This is because atrial fibrillation may start or stop on its own.
Symptoms may include:
- Pulse that feels rapid, racing, pounding, fluttering, irregular, or too slow
- Sensation of feeling the heart beat (palpitations)
Palpitations
Palpitations are feelings or sensations that your heart is pounding or racing. They can be felt in your chest, throat, or neck. You may:Have an unpl...
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Confusion
Confusion is the inability to think as clearly or quickly as you normally do. You may feel disoriented and have difficulty paying attention, remembe...
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Dizziness
Dizziness is a term that is often used to describe 2 different symptoms: lightheadedness and vertigo. Lightheadedness is a feeling that you might fai...
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Fainting
Fainting is a brief loss of consciousness due to a drop in blood flow to the brain. The episode most often lasts less than a couple of minutes and y...
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Fatigue
Fatigue is a feeling of weariness, tiredness, or lack of energy.
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- Shortness of breath
Exams and Tests
The health care provider may hear a fast heartbeat while listening to your heart with a stethoscope. Your pulse may feel fast, uneven, or both.
The normal heart rate is 60 to 100 beats per minute. In atrial fibrillation or flutter, the heart rate may be 100 to 175 beats per minute. Blood pressure may be normal or low.
An ECG (a test that records the electrical activity of the heart) may show atrial fibrillation or atrial flutter.
ECG
An electrocardiogram (ECG) is a test that records the electrical activity of the heart.

If your abnormal heart rhythm comes and goes, you may need to wear a special monitor to diagnose the problem. The monitor records the heart's rhythms over a period of time.
- Event monitor (3 to 4 weeks)
- Holter monitor (24-hour test)
Holter monitor
A Holter monitor is a machine that continuously records the heart's rhythms. The monitor is worn for 24 to 48 hours during normal activity.
ImageRead Article Now Book Mark Article - Implanted loop recorder (extended monitoring)
Tests to find heart disease may include:
- Echocardiogram (ultrasound imaging of the heart)
Echocardiogram
An echocardiogram is a test that uses sound waves to create pictures of the heart. The picture and information it produces is more detailed than a s...
ImageRead Article Now Book Mark Article - Tests to examine the blood supply of the heart muscle
- Tests to study the heart's electrical system
Tests to study the heart's electrical s...
Intracardiac electrophysiology study (EPS) is a test to look at how well the heart's electrical signals are working. It is used to evaluate abnormal...
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Treatment
Cardioversion treatment is used to get the heart back into a normal rhythm right away. There are two options for treatment:
Cardioversion
Cardioversion is a method to bring an abnormal heart rhythm back to normal.

- Electric shocks to your heart
- Drugs given through a vein
These treatments may be done as emergency methods, or planned ahead of time.
Daily medicines taken by mouth are used to:
- Slow the irregular heartbeat -- These drugs may include beta-blockers, calcium channel blockers, and digoxin.
- Prevent atrial fibrillation from coming back -- These drugs work well in many people, but they can have serious side effects. Atrial fibrillation returns in many people, even while they are taking these medicines.
A procedure called radiofrequency ablation can be used to scar areas in your heart where the heart rhythm problems are triggered. This can prevent the abnormal electrical signals that cause atrial fibrillation or flutter from moving through your heart. You may need a heart pacemaker after this procedure. All people with atrial fibrillation will need to learn how to manage this condition at home.
Radiofrequency ablation
Cardiac ablation is a procedure that is used to scar small areas in your heart that may be involved in your heart rhythm problems. This can prevent ...
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A pacemaker is a small, battery-operated device. This device senses when your heart is beating too slowly. It sends a signal to your heart that mak...

Manage this condition at home
Atrial fibrillation or flutter is a common type of abnormal heartbeat. The heart rhythm is fast and irregular. You were in the hospital to treat th...
Read Article Now Book Mark ArticlePeople with atrial fibrillation will most often need to take blood thinner medicines. These medicines are used to reduce the risk of developing a blood clot that travels in the body (and that can cause a stroke, for example). The irregular heart rhythm that occurs with atrial fibrillation makes blood clots more likely to form.
Blood thinner medicines include heparin, warfarin (Coumadin), apixaban (Eliquis), rivaroxaban (Xarelto), edoxaban (Savaysa) and dabigatran (Pradaxa). Antiplatelet drugs such as aspirin or clopidogrel may also be prescribed. However, blood thinners increase the chance of bleeding, so not everyone can use them.
Blood thinner medicines
You have gastroesophageal reflux disease (GERD). This condition causes food or stomach acid to come back into your esophagus from your stomach. Thi...
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Your health care provider prescribed a blood thinning medicine called heparin. It has to be given as a shot at home. A nurse or other health profess...
Read Article Now Book Mark ArticleWarfarin
Warfarin is a medicine that makes your blood less likely to form clots. It is important that you take warfarin exactly as you have been told. Chang...
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Current guidelines recommend that people with coronary artery disease (CAD) receive antiplatelet therapy with either aspirin or clopidogrel. Aspirin ...

Clopidogrel
Platelets are small cells in your blood that your body uses to form clots and stop bleeding. If you have too many platelets or your platelets stick ...

Another stroke prevention option for people who cannot safely take these medicines is the Watchman Device, which has recently been approved by the FDA. This is a small basket-shaped implant that is placed inside the heart to block off the area of the heart where most of the clots form. This limits clots from forming.
Your provider will consider your age and other medical problems when deciding which stroke prevention methods are best for you.
Outlook (Prognosis)
Treatment can often control this disorder. Many people with atrial fibrillation do very well with treatment.
Atrial fibrillation tends to return and get worse. It may come back in some people, even with treatment.
Clots that break off and travel to the brain can cause a stroke.
Stroke
A stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a "brain attack. " If blood flow is cut off for longer th...

When to Contact a Medical Professional
Contact your provider if you have symptoms of atrial fibrillation or flutter.
Prevention
Talk to your provider about steps to treat conditions that cause atrial fibrillation and flutter. Avoid binge drinking.
References
Calkins H, Tomaselli GF, Morady F. Atrial fibrillation: clinical features, mechanisms, and management. In: Libby P, Bonow RO, Mann DL, Tomaselli GF, Bhatt DL, Solomon SD, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia, PA: Elsevier; 2022:chap 66.
Heidenreich PA, Estes NAM 3rd, Fonarow GC, et al. 2020 Update to the 2016 ACC/AHA Clinical Performance and Quality Measures for adults with atrial fibrillation or atrial flutter: A report of the American College of Cardiology/American Heart Association Task Force on Performance Measures. J Am Coll Cardiol. 2021;77(3):326-341. PMID: 33303319 pubmed.ncbi.nlm.nih.gov/33303319/.
January CT, Wann LS, Calkins H, et al. 2019 AHA/ACC/HRS focused update of the 2014 AHA/ACC/HRS guideline for the management of patients with atrial fibrillation: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society in collaboration with the Society of Thoracic Surgeons. Circulation. 2019;140(6)e285. PMID: 30686041 pubmed.ncbi.nlm.nih.gov/30686041.
Lip GYH, Banerjee A, Boriani G, et al. Antithrombotic therapy for atrial fibrillation: CHEST Guideline and Expert Panel Report. Chest. 2018;154(5):1121-1201. PMID: 30144419 pubmed.ncbi.nlm.nih.gov/30144419/.
Zimetbaum P. Supraventricular cardiac arrhythmias. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 58.
Heartbeat
Animation
What makes your heart beat?
Animation
Atrial fibrillation
Animation
Atrial fibrillation overview
Animation
Heart - section through the middle - illustration
The interior of the heart is composed of valves, chambers, and associated vessels.
Heart - section through the middle
illustration
Heart - front view - illustration
The external structures of the heart include the ventricles, atria, arteries and veins. Arteries carry blood away from the heart while veins carry blood into the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.
Heart - front view
illustration
Anterior heart arteries - illustration
The coronary arteries supply blood to the heart muscle. The right coronary artery supplies both the left and the right heart; the left coronary artery supplies the left heart.
Anterior heart arteries
illustration
Conduction system of the heart - illustration
The intrinsic conduction system sets the basic rhythm of the beating heart by generating impulses which stimulate the heart to contract.
Conduction system of the heart
illustration
Heartbeat
Animation
What makes your heart beat?
Animation
Atrial fibrillation
Animation
Atrial fibrillation overview
Animation
Heart - section through the middle - illustration
The interior of the heart is composed of valves, chambers, and associated vessels.
Heart - section through the middle
illustration
Heart - front view - illustration
The external structures of the heart include the ventricles, atria, arteries and veins. Arteries carry blood away from the heart while veins carry blood into the heart. The vessels colored blue indicate the transport of blood with relatively low content of oxygen and high content of carbon dioxide. The vessels colored red indicate the transport of blood with relatively high content of oxygen and low content of carbon dioxide.
Heart - front view
illustration
Anterior heart arteries - illustration
The coronary arteries supply blood to the heart muscle. The right coronary artery supplies both the left and the right heart; the left coronary artery supplies the left heart.
Anterior heart arteries
illustration
Conduction system of the heart - illustration
The intrinsic conduction system sets the basic rhythm of the beating heart by generating impulses which stimulate the heart to contract.
Conduction system of the heart
illustration
Review Date: 1/1/2023
Reviewed By: Michael A. Chen, MD, PhD, Associate Professor of Medicine, Division of Cardiology, Harborview Medical Center, University of Washington Medical School, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.