Atrial fibrillation is a type of arrhythmia. With atrial fibrillation, the electrical signals in the atria (the two small chambers of the heart) are fired in a very fast and uncontrolled manner. The atria quiver instead of contract. The electrical signals then arrive in the ventricles in an irregular fashion.

When atria do not contract effectively, the blood may pool and/or clot. If a blood clot becomes lodged in an artery in the brain, a stroke (brain attack) may occur. About 15 percent of strokes occur in persons with atrial fibrillation.


Read about our annual Atrial Fibrillation Patient Reunion