Implantable devices versus antiarrhythmic drug therapy in recurrent ventricular tachycardia and ventricular fibrillation.

The implantable cardioverter defibrillator (ICD) protects patients from sudden cardiac death due to ventricular tachyarrhythmias. The capability of an improved overall survival of high-risk patients in comparison to the best pharmacologic therapy has been evaluated over the last few years in prospective randomized trials. In patients with a history of resuscitated ventricular fibrillation (VF) or unstable ventricular tachycardia (VT), the ICD was superior to therapy with amiodarone in 3 large trials involving 2,024 patients. At 2-year follow-up, ICD therapy was associated with a relative reduction in the risk of death of 20% to 30%. With respect to primary prevention of arrhythmogenic death, data are less convincing. The Multicenter Automatic Implantable Defibrillator (MADIT) study proved superiority of ICD therapy over medical treatment in coronary patients with depressed left ventricular function, nonsustained VT, and inducible but not suppressible sustained VT/VF. The second trial, the Coronary Artery Bypass Graft (CABG)-Patch trial, failed to show a similar superiority in 900 patients with an ejection fraction of < or = 35% and an abnormal signal-averaged electrocardiograph undergoing coronary artery bypass grafting. Thus, the role of device therapy for primary prevention of sudden death has not been established. Future prospective studies are needed to clarify this issue.