Abstract 16771: Longitudinal Segmental Shape Analysis of the Remodeling Left Ventricle in Chronic Mitral Regurgitation

Abstract

Introduction: Severe mitral regurgitation (MR) initiates left ventricular (LV) dilatation, but preserves systolic function. Due to preserved EF, patients are not referred for correction of their MR, and the ventricle continues to enlarge. Identifying patients at risk of heart failure, just from assessing LV size is challenging. In this study, we sought to investigate if ventricular shape and sphericity can represent the pathological remodeling process in this disease. Methods: Sixty adult rats (N=60) were induced with severe MR by puncturing the mitral valve leaflet with a 23G needle on the beating heart, using echo guidance (Fig.A1). Transthoracic echocardiography was performed at 2, 10, 20, and 40 weeks (n=15 rats/group) for analysis of the left ventricular shape. Fifteen healthy rats (N=15) were used as a sham group for comparison. Results: Severe MR was confirmed in all the rats in the MR group with a MR jet area of 40.99±9.40% ( Fig.A2 ), MR volume of 119.50±32.43μl ( Fig.A3 ), and pulmonary flow reversal ( Fig.A4 ). None of these were observed in the control group. LV dilation was observed in MR rats compared to sham ( Fig.B ). Diastolic sphericity index, LV area, and diastolic apical area index was significantly increased at 2, 10, 20, and 40 weeks after MR compared to sham (p<0.05) ( Fig.C1-C3 ). Systolic sphericity index was not significantly increased compared to sham at any time-point ( Fig.D1 ). LV area was unchanged at 2 weeks, and was significantly increased at 10, 20, and 40 weeks ( Fig.D2 ). Systolic apical area index was significantly increased at 2, 20, and 40 weeks compared to sham (p<0.05) ( Fig.D3 ). Conclusions: Analysis of left ventricular shape and its longitudinal changes can help detect remodeling patterns that are not visible using traditional functional indices.