Atrial fibrillation (A-fib or AF) is the most common type of sustained cardiac arrhythmia. It occurs when there are too many electrical signals that normally control the heartbeat, causing the upper chambers of the heart (the atria) to beat extremely rapidly (more than 400 beats per minute) and quiver (fibrillate).

Can AFib occur at any age?

Your risk of developing atrial fibrillation, a common heart rhythm disorder, increases as you become older. Atrial fibrillation is much more common in older adults. Atrial fibrillation can occur at any age, but when it develops in younger people, it's usually associated with other heart conditions.

Does atrial fibrillation come on suddenly?

Paroxysmal atrial fibrillation can come on randomly and suddenly, with symptoms lasting hours or sometimes just minutes. It doesn't last more than a week and the episodes usually end on their own.