Abstract: AIM:To investigate the prognostic significance of left ventricular (LV) systolic dyssynchrony in nonischemic dilated cardiomyopathy (DCM) using tissue Doppler echocardiography (TDI). METHODS: The study was conducted in 62 patients with nonischemic DCM. All patients were examined by electrocardiography TDI and angiography. Patients were allocated into two groups: group 1-10 patients with intraventricular delay (IVD)≤65 msec and group 2-52 patients with IVD >65 msec. The primary endpoint was defined as overall mortality during a mean follow-up period. RESULTS: Patients in group 2 had significantly longer mean IVD ［(129±68) msec vs. (58±9) msec; P<0.05］, higher rate of left bundle branch block (31% vs. 10%; P=0.05), longer QRS duration ［(145±29) msec vs. (129±23) msec; P<0.05］ and higher fatality rate (56% vs. 10%; P<0.01). Sudden cardiac death occurred in one patient in group 1 but in 12 patients in group 2. All the remaining deaths (n=17) occurred in group 2. Kaplan-Meier survival analysis showed a significantly lower survival in group 2 (P<0.05) and multivariate analysis showed that IVD was the only significant independent predictor of mortality (P<0.01). CONCLUSION: Increased IVD is associated with increased risk for death in patients with nonischemic DCM, independent of the QRS width and LV ejection fraction.