The current status of the implantable cardioverter defibrillator.

Since its initial application in 1980, the implantable cardioverter defibrillator (ICD) has evolved into a highly sophisticated device that offers programmable tiered therapy (antitachycardia pacing, cardioversion, and defibrillation) for ventricular tachyarrhythmias and backup pacing for bradycardia. It also provides diagnosis information about detected events. Successful implantation of nonthoracotomy systems is now routine. The availability of nonthoracotomy systems has reduced perioperative morbidity and mortality as well as hospital costs. Although the ICD has virtually eliminated sudden cardiac death in recipients, overall cardiac mortality remains considerable in these patients. Several prospective randomized clinical trials comparing ICD therapy to antiarrhythmic drug therapy are under way.