BACKGROUND: Left ventricular noncompaction (LVNC) is a rare, congenital cardiomyopathy and can be associated with heart failure, embolic events, arrhythmias, and sudden cardiac death. Implantation of implantable cardioverter-defibrillators in these patients is a treatment option, but data on long-term follow-up are limited. The aim of the study was to analyze the clinical outcome of patients with LVNC who were treated with an implantable cardioverter-defibrillator (ICD). METHODS:We conducted a retrospective study on 12 patients (mean age: 45 +/- 13 years, range 20-60) with LVNC, who underwent ICD implantation for secondary (n = 8) and primary (n = 4) prevention. RESULTS: During a median follow-up of 36 months, five patients (42%) presented with appropriate ICD therapy: in four of the eight patients (50%) in whom the ICD was implanted as a secondary prevention and in one of the four patients (25%) for whom the ICD was implanted for primary prevention. In eight patients (66%) supraventricular tachyarrhythmias were documented. Improvement of left ventricular function could be observed in one of two patients with a biventricular ICD. CONCLUSIONS: Potentially life-threatening ventricular tachyarrhythmias may occur in patients with LVNC. ICD therapy may be effective for primary and secondary prevention in these patients. Due to the high prevalence of supraventricular tachyarrhythmias devices with reliable detection enhancements should be considered.