Prognostic significance of left ventricular systolic dyssynchrony in patients with nonischemic dilated cardiomyopathy

Objectives: Left ventricular (LV) dyssynchrony parameters are still being investigated to guide and optimize treatment in heart failure. We investigated the prognostic importance of LV systolic dyssynchrony in nonischemic dilated cardiomyopathy (DCM) using tissue Doppler echocardiography. Study design: The study included 62 patients (39 males, 23 females; mean age 40 years; range 9 to 77 years) with nonischemic DCM. All the patients were examined by electrocardiography, echocardiography including tissue Doppler imaging (TDI), and angiography. The patients were evaluated in two groups depending on the intraventricular delay (IVD) of <= 65 msec (group 1, 10 patients) and >65 msec (group 2, 52 patients). The primary endpoint was defined as overall mortality during a mean follow-up period of 1,253 +/- 177 days (range 943 to 1583 days). Results: Group 2 patients had a significantly longer mean IVD (129 +/- 68 msec vs. 57.5 +/- 8.7 msec; p=0.013), higher rate of left bundle branch block (30.8% vs. 10%; p= 0.05), longer QRS duration (145 +/- 29 msec vs. 129 +/- 23 msec; p= 0.02), and higher mortality (55.8% vs. 10%; p<0.0001). Sudden cardiac death was seen in one patient in group 1, compared to 12 patients in group 2. All the remaining deaths (n= 17) occurred in group 2. In ROC analysis, the cutoff level for IVD was 65 msec for predicting clinical endpoint (specificity 72%, sensitivity 46%). Kaplan-Meier survival analysis showed a significantly lower survival in group 2 (p= 0.045). In multivariate analysis, admission IVD was the only significant independent predictor of mortality (p<0.001). Conclusion: Our results showed that increased IVD was associated with increased risk for death in patients with nonischemic DCM, independent from the QRS width and LV ejection fraction. These patients might be considered earlier for cardiac resynchronization therapy.