You know the signs...rapid heart beat... shortness of breath... panic! Sounds like a heart attack, or panic disorder. More often, it is Atrial Fibrillation, an irregular heartbeat disorder than can cause the heart to beat more than 300 times a minute. More than 2 million people have Atrial Fibrillation. Here's what happens: because of a problem with the electrical wiring in the heart, the two small upper chambers, the atria, quiver instead of beating effectively. This quivering causes the discomfort the patient feels, and can cause the blood to pool and clot. If a piece of blood clot leaves the heart and becomes lodged in an artery in the brain, a stroke results. About fifteen percent of strokes occur in people with Atrial Fibrillation. There are effective treatments for Atrial Fibrillation including medication and a minimally invasive surgery.