Holter monitoring was performed in 202 patients with idiopathic dilated cardiomyopathy, which revealed accelerated idioventricular rhythm in 16 patients (8%) and nonsustained ventricular tachycardia in 70 patients (35%). During 32 +/- 15-month prospective follow-up, no significant difference was observed for major arrhythmic events and transplant-free survival between patients with and without accelerated idioventricular rhythm, whereas patients with nonsustained ventricular tachycardia had a significantly higher incidence of major arrhythmic events and a lower transplant-free survival rate.