Improvement of Left Ventricular Function after Cardiac Resynchronization Therapy Is Predicted by Tissue Doppler Imaging Echocardiography

Abstract

Background - Cardiac resynchronization therapy was shown to reverse left ventricular (LV) remodeling in patients with congestive heart failure (CHF). However, the prediction of benefit is controversial. We aimed to investigate predictive factors of LV functional recovery and reversed remodeling after biventricular pacing. Methods and Results - Forty-nine consecutive patients with CHF and a wide QRS complex (182±32 ms) were studied by echocardiography before resynchronization. Intraventricular and interventricular asynchrony and their combination were assessed by pulsed-wave tissue Doppler imaging from measurements of regional electromechanical coupling times in basal segments of the right and left ventricle. At 6-month follow-up, responders were defined by a relative increase in LV ejection fraction ≥25% compared with baseline (n=27). Receiver operating curve analysis revealed the degree of intraventricular asynchrony (area under the curve=0.77), interventricular asynchrony (area under the curve=0.69), and their combination (area under the curve=0.84) as the best predictors of functional recovery after resynchronization. In addition, the degree of intraventricular and interventricular asynchrony correlated significantly with the improvement of LV ejection fraction (r=0.73, P<0.0001), end-diastolic diameter (r=-0.59, P<0.0001), and end-systolic diameter (r=-0.48, P<0.001) at follow-up. QRS duration and conventional echo-Doppler indices were not predictive of reversed LV remodeling. Conclusions - In patients with CHF, the degree of intraventricular and interventricular asynchrony and their combination are the best predictive factors of LV functional recovery and reversed remodeling after cardiac resynchronization therapy.