Abnormal electrical signals

Atrial fibrillation is probably a diagnosis you have heard of, if not because a friend or family member has it, because it has been mentioned in a public advertisement or pharmaceutical commercial. Atrial fibrillation (or "A-fib") is the most common cardiac arrhythmia, a condition estimated by the American Heart Association to be present in more than five million Americans.

A-fib happens when abnormal electrical signals occurring throughout the cardiac atria (upper chambers of the heart) override the normal intrinsic electrical pacemaker. Sometimes this causes symptoms such as heart palpitatio...