Left Ventricular Dyssynchrony Predicts Clinical Response to CRT – A Long‐Term Follow‐Up Single‐Center Prospective Observational Cohort Study

Background Until now, there is no consensus regarding the definition of a clinical response to cardiac resynchronization therapy ( CRT ) in patients with chronic heart failure ( CHF ) and systolic left ventricular ( LV ) dysfunction. The aim of this study was to evaluate if echocardiography is predictive for an objective improvement in exercise capacity during long‐term follow‐up of CRT . Methods Each patient underwent echocardiography and spiroergometry both at baseline and at last follow‐up. Left ventricular dyssynchrony ( LVD ) before CRT was defined by tissue Doppler imaging ( TDI ) as intra‐ LV delay ≥40 msec (septal‐lateral or anterior‐posterior). Clinical response to CRT was defined as increase of peak VO 2 or as increase of maximal workload >10% as compared to baseline. Results Mean follow‐up was 69 ± 37 months. From the 238 consecutive patients included in the study, 141 (59%) were classified as clinical responders and 97 (41%) as nonresponders. Baseline data of responders and nonresponders were comparable. However, clinical responders showed more often LVD (64%) than nonresponders (42%, P = 0.004). On multivariate regression analysis, nonischemic origin of CHF (β‐coefficient in the final model 0.1, P = 0.04) and LVD at baseline (β‐coefficient in the final model 0.2, P < 0.001) were independently associated with clinical response during long‐term follow‐up. Patients with LVD at baseline had significant more often an improvement of left ventricular ejection fraction >10% (P = 0.02) and a reduction of left ventricular end‐diastolic diameter ( LVEDD ) >10% (P < 0.01) than patients without LVD at baseline. Conclusions LVD at baseline as assessed by a straightforward echocardiographic approach predicts the long‐term clinical response to CRT and is associated with a more pronounced reverse LV remodeling.