The implantable cardioverter defibrillator and primary prevention of sudden death: The Multicenter Automatic Defibrillator Implantation Trial and theCoronary Artery Bypass Graft (CABG)-Patch Trial

The Multicenter Automatic Defibrillator implantation Trial (MADIT) and the Coronary Artery Bypass Graft (CABG)-Patch study were the first 2 randomized trials investigating the usefulness of the implanted cardioverter defibril lator CCD) for primary prevention of sudden death. patients enrolled in MAD IT and CABG-Patch had never experienced a sustained ventricular tachycardia (VT) but were thought to be at high risk of sudden death. All patients had coronary artery disease and severely suppressed left ventricular ejection fraction. CABG-Patch patients received their ICD during CABG surgery. Most MADIT patients already had received CABG or percutaneous transluminal coron ary angiography and had no indication for revascularization procedures at s tudy entry. MADIT patients had nonsustained spontaneous VT and inducible, n onsuppressible VT; CABG-Patch patients had only an abnormal signal-averaged electrocardiogram as an indicator of their arrhythmic risk. CABG-Patch pat ients did not benefit from ICD implantation, presumably due to the influenc e of revascularization on ischemia and left ventricular function. In contra st, MADIT patients showed an improved survival by the ICD. MADIT patients h ad no need for revascularization and, presumably, their risk indicator for arrhythmic events was stronger than the one used in CABG-Patch. MADIT crite ria have become a class indication for ICD implantation and, in the absence of testing for suppressibility of induced VTs, a class IIb criterion for I CD implantation. Screening for MADIT patients is expensive, as only relativ ely few patients after myocardial infarction fulfill the criteria. Neverthe less, in comparison with amiodarone, treatment of MADIT patients with ICDs seems to be cost-effective, especially if ICDs are implanted transvenously and have the improved battery longevity of the current devices. (C) 1999 by Excerpta Medica, Inc.