The Automatic Implantable Cardioverter/Defibrillator

Abstract

It is currently recognized that patients with a history of recurrent sustained ventricular tachycardia or with ventricular fibrillation not associated with acute myocardial infarction or other reversible cause are at high risk for sudden cardiac death. Although some deaths in these patient populations are due to progressive congestive heart failure, approximately 2/3 are sudden and presumably preventable. Electrophysiologic testing has indicated that those patients treated with drugs which permit continued induction of sustained ventricular tachyarrhythmias have a 25–30% one year sudden death rate (1). Even patients treated with drugs rendering them noninducible at electrophysiologic study have a one year sudden death rate approaching 10%. Those patients who fail a number of drugs at serial electrophysiologic testing are considered excellent candidates for alternative therapies such as amiodarone, endocardial mapping with resection or cryoablation and/or automatic cardioverter/defibrillator (AICD) implantation. Long-term amiodarone therapy is associated with a high failure rate due to side effects, arrhythmia recurrences and sudden death. In our experience, the one year actuarial sudden death rate for patients receiving amiodarone is 16.7% and after 2 years only approximately 1/3 of patients remain effectively treated with the drug (2).