Abstract 16215: Ventricular Dyssynchrony is Associated With Arrhythmic Mitral Prolapse Prior to Chamber Remodeling
Introduction: Asymptomatic patients on active surveillance for degenerative mitral regurgitation are at risk of ventricular arrhythmia and sudden death. Hypothesis: Abnormal myocardial mechanics may precede ventricular remodeling and may help identify at-risk patients. Methods: Multi-directional myocardial mechanics and LV dyssynchrony were assessed in 204 consecutive patients awaiting surgical mitral repair for severe degenerative MR in a quaternary mitral reference center. Results: The mean age was 58 ±12.5 years and 40% were females. The mean EF was 63% ± 6% and 92% had compensated LV function (EF>60% and LVESD<4cm) and only 24% had elevated LV filling pressures (E/e'≥13). Indexed LV wall stress-to-LVEDD, relative wall thickness and indexed LV mass-to-BSA were similar amongst males-females, although males had higher mean blood pressure (94 Vs. 90, P=0.02) . The peak global longitudinal strain (GLS) was -25.2% ± 3.3% and the mid-ventricular circumferential and radial strains were -33.5%±6.7% and 56%±25% respectively. Ventricular ectopy was present in 24.5% of patients and only 17% had atrial fibrillation (Afib) despite the significantly dilated left atria (mean LAVi 70±26.6 ml/m 2 ). The median LV mechanical dispersion was 40msec (IQR 30.7-56.5) but increased significantly with ventricular ectopy (65msec, P<0.01) and further influenced by concomitant Afib (p=0.001 for 2-factor interaction). Diastolic LV function did not correlate with dispersion (r=0.02 and 0.01 for E/A and E/e', P=NS) but was associated with the duration of LV diastolic filling (mean 502±140msec; r=0.2, P=0.004). Interpapillary radial strain delay was noted in the study cohort (mean delay 52.8msec, range 0-335msec) while intepapillary activation delay was manifested with concomitant ventricular ectopy (mean time-to-peak LS delay 57.5±48msec). Conclusions: Left ventricular dyssynchrony manifested by increased mechanical dispersion and imbalanced interpapillary mechanics are observed prior to overt chamber remodeling in significant degenerative MR and is associated with ventricular ectopy. Further studies are needed to assess the related clinical implications and potential impact on risk stratification in this patient group.