The implantable cardioverter defibrillator and primary prevention of sudden death: the Multicenter Automatic Defibrillator Implantation Trial and the Coronary 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 defibrillator (ICD) for primary prevention of sudden death. Patients enrolled in MADIT 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 coronary angiography and had no indication for revascularization procedures at study entry. MADIT patients had nonsustained spontaneous VT and inducible, nonsuppressible VT; CABG-Patch patients had only an abnormal signal-averaged electrocardiogram as an indicator of their arrhythmic risk. CABG-Patch patients did not benefit from ICD implantation, presumably due to the influence of revascularization on ischemia and left ventricular function. In contrast, MADIT patients showed an improved survival by the ICD. MADIT patients had no need for revascularization and, presumably, their risk indicator for arrhythmic events was stronger than the one used in CABG-Patch. MADIT criteria have become a class I indication for ICD implantation and, in the absence of testing for suppressibility of induced VTs, a class IIb criterion for ICD implantation. Screening for MADIT patients is expensive, as only relatively few patients after myocardial infarction fulfill the criteria. Nevertheless, 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.