Sudden Electrical Death.

The new millennium will mark the 20th anniversary of the first implantable cardioverter defibrillator implantation in 1980. During this relatively short period of time, the device has gone from a therapy of last resort for cardiac arrest survivors to a mainstay of treatment for malignant ventricular arrhythmias. Previously implanted only via thoracotomy, the ICD is now a small transvenous device system and is often used as prophylactic therapy for the high-risk patient. In April 1998, the American Heart Association and the American College of Cardiology, in conjunction with the North American Society for Pacing and Electrophysiology (NASPE), published updated indications for the implantation of the ICD (Table 1) [1••]. For the first time, these recommendations were based on the results of prospective, randomized, controlled clinical trials. Analysis of these guidelines and the studies that led to them places the current status of ICD therapy in perspective and provides us with a view of future directions. The strongest recommendations by the Pacemaker and ICD Implantation Committee were for the Class I conditions. Class I conditions are those for which there is “evidence and/or general agreement that the ICD is beneficial, useful, and effective.” These include 1) cardiac arrest due to ventricular fibrillation (VF) or ventricular tachycardia (VT) not due to a transient or reversible cause; 2) spontaneous sustained VT; 3) syncope of undetermined origin with clinically relevant, hemodynamically significant sustained VT or VF induced during electrophysiology study (EPS) when drug therapy is ineffective, not tolerated, or not preferred; and 4) nonsustained VT with coronary disease, prior myocardial infarction, left ventricular dysfunction, and inducible VT or VF induced during EPS that is not suppressible with intravenous procainamide. These recommendations were based largely on several large “postevent” trials (ie, those involving patients who had survived a significant ventricular arrhythmia) as well as the results of the Multicenter Automatic Defibrillator Implant Trial (MADIT), a “preevent” trial of survivors of myocardial infarction with left ventricular dysfunction and nonsustained VT (Table 2) [2•]. Early retrospective reports quickly confirmed the remarkable efficacy of the ICD in preventing sudden death [3–5]. Some retrospective studies found improved survival in patients treated with the ICD compared with amiodarone [6,7]. These studies suffered from variable technology use, variable patient selection, and variable alternative treatment options, however. Additionally, the effect of the ICD on sudden death recurrence was often reported as being opposed to the effect on total mortality. Many critics of the ICD suggested that despite the beneficial treatment of malignant arrhythmias, most patients would succumb to left ventricular dysfunction without realizing prolonged survival with the ICD [8–10]. Opinion statement