1159 Right ventricular electromechanical dyssynchrony in relation to right ventricular remodeling, dysfunction and exercise capacity in Ebstein anomaly

Abstract Background Abnormal atrioventricular conduction and functional right ventricular (fRV) dysfunction are common in patients with Ebstein anomaly (EA). However, the relation of fRV dyssynchrony to fRV function in EA has not been studied. Purpose We hypothesized that fRV electromechanical dyssynchrony is associated with fRV remodeling, dysfunction and exercise intolerance in EA patients. Methods Non-operated EA patients and age-matched controls prospectively underwent echocardiography, cardiovascular magnetic resonance imaging (CMR) and cardiopulmonary exercise testing to quantify RV remodeling, dysfunction and exercise capacity, respectively. The relation of these to fRV dyssynchrony was investigated. RV mechanical dyssynchrony was defined by early septal activation (right-sided septal flash), RV lateral wall prestretch/late contraction, postsystolic shortening, and the maximal intra-RV delay (difference in time to peak of lateral basal RV and apical septal segments) using 2-dimensional strain echocardiography. Results Thirty-five EA patients (age 31.6 ± 17.3 years, 19 female) and 35 age-matched controls were studied. QRS duration and intra-fRV mechanical delay were significantly longer in EA compared with controls. 19/35(54%) of EA patients had early activation of septal segments with simultaneous stretching and consequent late activation and post-systolic shortening of RV lateral segments. QRS duration correlated with fRV end-diastolic (fRVEDVI, r = 0.46, P <0.01) and end-systolic indexed volumes (fRVESVIr = 0.57, P <0.001). Intra-fRV delay correlated with RV global longitudinal strain (GLS, r=-0.45,P <0.05) and RV fractional area change (r=-0.56, P <0.01). Intra-fRV delay was also associated with fRVEDVI (r = 0.43, P <0.05), fRVESVI (r = 0.63, P <0.001), fRVEF (r=-0.46,P <0.05) and predicted peak VO2 (r=-0.39, P < 0.05). EA patients with versus without a septal flash had lower fRVEF (45 ± 11 vs. 54 ± 8%, p < 0.05) and predicted peak VO2 (0.71 ± 0.19 vs. 0.92 ± 0.33, p < 0.05). Conclusions In EA, fRV electromechanical dyssynchrony is associated with fRV remodeling, dysfunction and impaired exercise capacity and may constitute a therapeutic target. Abstract 1159 Figure.