Predicting factors of echocardiographic super-response to cardiac resynchronization therapy.

Purpose: To investigate the clinical and echocardiographic predictors of echocardiographic super-response to cardiac resynchronization therapy (CRT) in heart failure patients.

Methods: We retrospectively collected data from 97 patients, who underwent CRT and were followed up (median time = 20.33 months). All had left ventricular ejection fraction (LVEF) ≤35%, New-York-Heart-Association class 3 or 4, and Q wave, R wave and S wave (QRS) duration >120 ms. Time-to-peak systolic velocity was measured for individual LV segments by tissue Doppler imaging prior to CRT. Two-dimensional echocardiography was carried out before and at follow-up, and ≥12.5% increase in LVEF was defined as super-response.

Results: From the 97 patients, 23 (23.7%) were super-responders. Super-responders were more frequently female (52.2% vs. 24.3%, respectively; p value = 0.012). Among super-responders, the mean of LV end-diastolic and end-systolic volumes were significantly lower. According to dyssynchrony indices, time delay between anteroseptal and posterior wall and SD of all LV segments timing showed significantly higher values in super-responders. By multivariate analysis, LV end-systolic volume and anteroseptal-to-posterior wall delay remained independently associated with echocardiographic super-response to CRT.

Conclusion: About one-fourth of our patients with CRT were super-responder in that they had ≥12.5% increase in LVEF by echocardiography. Among all the clinical and echocardiographic measures, only lower LV end-systolic volume and higher anteroseptal-to-posterior wall delay predicted super-response.