Electrophysiology, or EP, is the sub-specialty of cardiology that addresses electrical problems of the heart. It is well known that the heart has arteries, the coronary arteries, that can become blocked over time and lead to heart attacks. What is not as well recognized by many is that the heart also has its own electrical system that keeps the four chambers, or parts, of the heart beating in an organized, rhythmic fashion. When extra circuitry develops or becomes apparent, or when there is a failure of the heart’s own electrical wiring, the heart may beat too fast or too slow. Patients will often complain of symptoms of palpitations, fatigue, shortness of breath, lightheadedness or may even pass out.