A radial global dyssynchrony index as predictor of left ventricular reverse remodeling after cardiac resynchronization therapy

Background: Cardiac mechanical efficiency requires that opposing left ventricular regions are coupled both in shortening and lengthening during the same phase of cardiac cycle. Aim of this study was to evaluate whether global measures of mechanical dyssynchrony are able to predict reverse remodeling of the left ventricle in patients receiving cardiac resynchronization therapy (CRT). Methods: Sixty-two patients underwent a clinical examination, including New York Heart Association class evaluation and 6-minute walking distance and both echocardiographic study before and 6 months after CRT. Intraventricular dyssynchrony was evaluated by two-dimensional strain echocardiography, measuring the amount of uncoordinated contraction and relaxation between septum and free wall for both longitudinal and radial function and was presented as the longitudinal global dyssynchrony index (LGDI) and the radial global dyssynchrony index (RGDI). Reverse remodeling was defined by a left ventricular end systolic volume reduction >= 15%. Results: After CRT 39 patients showed reverse remodeling. In this group, RGDI (0.74 +/- 0.26 vs 0.32 +/- 0.30; P = 0.0001) and LGDI (0.52 +/- 0.28 vs 0.30 +/- 0.24; P = 0.002) were significantly higher than in nonresponders. A receiver-operating characteristic curve analysis showed that RGDI > 0.47 and LGDI > 0.34 had a sensitivity and a specificity to predict reverse remodeling of 87% and 74%, 82%, and 74%, respectively. Stepwise forward multiple logistic regression analysis showed that RGDI (O.R.:13.4; 95%C.I.:4.2-120.5; P < 0.0001) was an independent determinant of a positive response to CRT. Conclusion: A radial global dyssynchrony index predicts left ventricular reverse remodeling after CRT.