Value of Tissue Doppler Echocardiography in Predicting Response to Cardiac Resynchronization Therapy in Patients With Heart Failure

Several studies have demonstrated a relation between left ventricular (LV) dyssynchrony and response to cardiac resynchronization therapy (CRT). Many methods of determining LV dyssynchrony have been proposed, including a value of 65 ms as assessed by tissue Doppler imaging. The aim of the present validation study was to prospectively test the predictive accuracy of the 65-ms cutoff for LV dyssynchrony in a large cohort of patients with heart failure undergoing CRT. The study included 361 patients who had undergone CRT. The clinical and echocardiographic parameters were assessed at baseline and at 6 months of follow-up. The clinical response was defined as an improvement of ≥1 New York Heart Association class, and the echocardiographic response was defined as a reduction in LV end-systolic volume of ≥15%. At 6 months of follow-up, 259 patients (72%) had a clinical response and 187 patients (52%) had an echocardiographic response. The patients with a response had more LV dyssynchrony than did those without a response (91 ± 49 ms vs 50 ± 44 ms for the clinical response and 101 ± 46 ms vs 55 ± 45 ms for the echocardiographic response). On multivariate analysis, LV dyssynchrony remained predictive of the response, independent of other characteristics. In conclusion, LV dyssynchrony of ≥65 ms was an independent predictor of both the clinical and the echocardiographic response in patients with heart failure who underwent CRT in this validation study.