Implantable devices for the treatment of cardiac arrhythmias.

The development of implantable devices for the treatment of tachyarrhythmias has resulted in additional therapeutic choices for the affected patients. Technologic advances now permit one to choose from a wide variety of devices capable of intervening automatically in the presence of supraventricular or ventricular arrhythmias. Although all methods remain in the investigational stage at this time, sufficient evidence has been gathered to support the efficacy of certain devices in the presence of various arrhythmias. Pacemaker-energy pulses may be delivered in various sequences to interrupt re-entrant rhythms, and their reproducible success can be effectively demonstrated in the electrophysiology laboratory. Cardioverting and defibrillating devices are capable of recognizing and successfully interrupting malignant ventricular arrhythmias. The automatic defibrillator has already been reported to reduce 1-year arrhythmic mortality in high-risk patients. Although still in the infant stages of development, the continuing advances in device technology suggest that their future applications are indeed promising.