The implantable cardioverter defibrillator (ICD) for patients at high risk of sudden cardiac death (primary prevention) has become an accepted therapy after multiple randomized trials demonstrated the benefit consistently. After years of extensive evaluation of the trial data, Center for Medicare and Medicaid Services(CMS) has approved the national registry that is endorsed by the American College of Cardiology and Heart Rhythm Society. Thus, ICD implantation for primary prevention of sudden cardiac death is one of the most intensively evaluated, strictly regulated and closely monitored therapies.