Cardioversion

From Heart Center Online: (free subscription necessary)

Also known as electrical cardioversion, cardioversion converts certain types of abnormal heart rhythms (arrhythmias) to normal ones. It accomplishes this with a well-controlled and perfectly timed electrical shock to the chest wall. Cardioversion is usually performed on a scheduled, outpatient basis, but is sometimes done in emergency situations. During the procedure, the patient will not feel any pain because he or she has received either general anesthesia or a strong sedative. The procedure has shown great success in correcting arrhythmias (e.g.atrial fibrillation) that have not improved with medication alone. Patients do, however, need to continueantiarrhythmic drugs after cardioversion.

While having some similarities to defibrillation, cardioversion differs in its use of much lower electricity levels. Cardioversion may also be done through medication instead of an electrical shock.