[Cardiac resynchronization therapy-always with ICD?].

Sudden cardiac death is responsible for about 50% of all deaths in heart failure. In studies on primary and secondary prevention of sudden cardiac death, the implantable cardioverter defibrillator (ICD) has proven superior to antiarrhythmic drug therapy mainly in patients with coronary artery disease and reduced left ventricular function. Thus, in recent years the question arose whether prophylactic ICD treatment can reduce mortality as well in an unselected patient group with heart failure of any etiology. This is even more important for patients that are candidates for cardiac resynchronization therapy because, first, presence of an intraventricular conduction delay indicates an increased risk of sudden death and, second, the additional operative morbidity of ICD implantation is minimal compared to implant of a biventricular pacemaker. Recent studies have proven the benefit of conventional ICD treatment in patients with heart failure as well as the benefit of biventricular pacing in heart failure patients with ventricular conduction delay. In the present article, these studies and their influence on the system choice in cardiac resynchronization therapy are discussed.