Related Conditions

Atrial fibrillation is an arrhythmia, or heartbeat abnormality. It occurs when multiple abnormal electrical impulses in the upper chambers of the heart (the atria) fire rapidly at the same time, causing the atria to quiver, or fibrillate.

Atrial fibrillation may interfere with the heart’s ability to fill with blood and pump normally. This, in turn, may prevent the body from receiving the necessary supply of blood and oxygen. 

Atrial fibrillation affects more than 2 million Americans, and each year more than 150,000 people are newly diagnosed. It is the most common cause of stroke.

Atrial fibrillation

Atrial fibrillation (say “A-tree-uhl fih-bruh-LAY-shun”) is an irregular heart rhythm (arrhythmia) that starts in the upper parts (atria) of the...


An abnormal heartbeat (arrhythmia) is any variation in the normal heartbeat. Abnormal heartbeats occur when the heart has an irregular heart...