What is the cause of atrial fibrillation?

Atrial fibrillation (AF) is diagnosed when abnormal, rapid, disorganized electrical signals cause the atria (the upper chambers of the heart) to quiver or beat erratically. This can cause blood to pool and form clots. If a clot breaks off and travels to the brain, it can cause a stroke. AF is the most common type of arrhythmia, or irregular heartbeat.

There are many possible causes of AF, including structural abnormalities of the heart, heart attack, high blood pressure, coronary artery disease, obesity, diabetes mellitus and sleep apnea. Some people develop AF for no known reason.