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Atrial Fibrillation (AF)

Atrial fibrillation, or AF, is the most common type of arrhythmia. An arrhythmia is a problem with the rate or rhythm of the heartbeat.

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(Source: NIH - National Heart, Lung, and Blood Institute)

Atrial Fibrillation

Atrial fibrillation (A-tre-al fi-bri-LA-shun), or AF, is the most common type of arrhythmia (ah-RITH-me-ah). An arrhythmia is a problem with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.

AF occurs if rapid, disorganized electrical signals cause the heart's two upper chambers - called the atria (AY-tree-uh) - to fibrillate. The term "fibrillate" means to contract very fast and irregularly.

In AF, blood pools in the atria. It isn't pumped completely into the heart's two lower chambers, called the ventricles (VEN-trih-kuls). As a result, the heart's upper and lower chambers don't work together as they should.

People who have AF may not feel symptoms. However, even when AF isn't noticed, it can increase the risk of stroke. In some people, AF can cause chest pain or heart failure, especially if the heart rhythm is very... Read more about Atrial Fibrillation

What works? Research summarized

Evidence reviews

Predictors of atrial fibrillation in patients following isolated surgical revascularization: a metaanalysis of 9 studies with 28 786 patients

Bibliographic details: Banach M, Misztal M, Goch A, Rysz J, Goch J H.  Predictors of atrial fibrillation in patients following isolated surgical revascularization: a metaanalysis of 9 studies with 28 786 patients. Archives of Medical Science 2007; 3(3): 229-239

Health technology assessment of different doses of metoprolol for atrial fibrillation

Bibliographic details: Wang H, Dong B R, Yang M.  Health technology assessment of different doses of metoprolol for atrial fibrillation. Chinese Journal of Evidence-Based Medicine 2008; 8(5): 334-339

Anticoagulants for preventing stroke in patients with nonrheumatic atrial fibrillation and a history of stroke or transient ischaemic attack

Anticoagulants are beneficial and safe for preventing a second stroke in people with nonrheumatic atrial fibrillation and recent cerebral ischaemia. Nonrheumatic atrial fibrillation (NRAF) is a heart rhythm disorder commonly found in patients who have had a stroke. Patients with NRAF have an irregular heart beat and this can cause the formation of a blood clot in the left atrium of the heart . This clot may break away and block a cerebral artery causing a stroke. Patients who have had a stroke in the presence of NRAF have a high risk of another stroke. Anticoagulant drugs, such as warfarin, make the blood 'thinner' and prevent the formation of blood clots and hence could prevent stroke. However, anticoagulant drugs may also cause bleeding in the brain and this complication could offset any benefits. This review identified two trials in which patients with NRAF who had a stroke were treated with anticoagulant therapy. These studies show that anticoagulants safely reduce the risk of recurrent stroke by two‐thirds, despite a higher chance of major extracranial bleeds. There was no increased risk of intracranial bleeds.

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Summaries for consumers

Radiofrequency Ablation for Atrial Fibrillation: A Guide for Adults

This guide talks about a procedure for people with A-fib that can put the heart back into normal rhythm. The procedure is called radiofrequency ablation (RFA). Ablation means removing problem areas. During RFA, doctors thread a thin wire through a vein to the heart. Then heat is sent through the wire to problem areas. The heat destroys a small amount of tissue and stops abnormal heart beats.

Anticoagulants for preventing stroke in patients with nonrheumatic atrial fibrillation and a history of stroke or transient ischaemic attack

Anticoagulants are beneficial and safe for preventing a second stroke in people with nonrheumatic atrial fibrillation and recent cerebral ischaemia. Nonrheumatic atrial fibrillation (NRAF) is a heart rhythm disorder commonly found in patients who have had a stroke. Patients with NRAF have an irregular heart beat and this can cause the formation of a blood clot in the left atrium of the heart . This clot may break away and block a cerebral artery causing a stroke. Patients who have had a stroke in the presence of NRAF have a high risk of another stroke. Anticoagulant drugs, such as warfarin, make the blood 'thinner' and prevent the formation of blood clots and hence could prevent stroke. However, anticoagulant drugs may also cause bleeding in the brain and this complication could offset any benefits. This review identified two trials in which patients with NRAF who had a stroke were treated with anticoagulant therapy. These studies show that anticoagulants safely reduce the risk of recurrent stroke by two‐thirds, despite a higher chance of major extracranial bleeds. There was no increased risk of intracranial bleeds.

Anticoagulants versus antiplatelet therapy for preventing stroke in patients with nonrheumatic atrial fibrillation and a history of stroke or transient ischemic attack

Anticoagulants are more effective than antiplatelet drugs to prevent a second stroke in people with atrial fibrillation. Nonrheumatic atrial fibrillation (NRAF) is a heart rhythm disorder commonly found in patients who have had a stroke. Patients with NRAF have an irregular heart beat. This can cause the formation of a blood clot in the left atrium of the heart. This clot may break away and block a cerebral artery, thus causing a stroke. Patients who have had a stroke in the presence of NRAF have a high risk of another stroke. Anticoagulant drugs, such as warfarin, make the blood 'thinner' and prevent the formation of blood clots and hence could prevent stroke. However, anticoagulant drugs may also cause bleeding in the brain and this complication could offset any benefits. Aspirin may be a safer alternative. This review identified two trials in which patients with NRAF who had a stroke were treated with anticoagulants or antiplatelet therapy. These studies show that anticoagulants are superior to antiplatelet agents to reduce the risk of recurrent stroke.

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Terms to know

Atria
The chambers of the heart, to which the blood returns from the circulation.
Heart Failure
A chronic condition in which the heart cannot pump blood properly.
Heart Ventricles
The lower right and left chambers of the heart.
Stroke (Cerebrovascular Accident)
A stroke occurs if the flow of oxygen-rich blood to a portion of the brain is blocked. Without oxygen, brain cells start to die after a few minutes. Sudden bleeding in the brain also can cause a stroke if it damages brain cells.

More about Atrial Fibrillation

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Also called: AFib

Other terms to know: See all 4
Atria, Heart Failure, Heart Ventricles

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