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 VO2 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. [ABSTRACT FROM AUTHOR]