Abstract 17767: Geometric Differences in the Mitral Apparatus Between Ischemic Cardiomyopathy and Lone Atrial Fibrillation with Significant Mitral Regurgitation: A Real-Time Three-Dimensional Echocardiography Study

Abstract

Introduction: Real-time three-dimensional transesophageal echocardiography (3D TEE) is a new technique that allows superior visualization of the mitral annulus and leaflet to two-dimensional TEE. We sought to elucidate the geometric differences in the mitral apparatus between lone atrial fibrillation (AF) and ischemic cardiomyopathy (ICM) with significant MR by 3D TEE. Methods: This study consisted of 20 patients (pts) with ischemic MR and 20 pts with functional MR due to lone AF. The severity of MR was evaluated on a basis of vena contract width (VCW). 3D TEE images were evaluated with dedicated mitral valve quantification software (Figure). Mitral annular anteroposterior (AP) and commissure-commissure (CC) diameters, AP-CC diameter ratio, area, and height which corresponds to annular saddle-shape depth (Figure) were analyzed at mid-systole. Tenting height, and tenting volume were also determined. Additionally, coaptation length (overlap length of the anterior and posterior leaflet) was measured in three locations; medial (CLm), central (CLc) and lateral (CLl). Results: No difference in VCW was found between lone AF pts and ischemic MR pts. Lone AF pts had greater AP (38 ± 5.0 vs. 30 ± 4.6 mm) and CC diameters (39 ± 4.9 vs. 33 ± 4.2 mm), AP-CC diameter ratio (0.99 ± 0.08 vs. 0.90 ± 0.06), and mitral annular area (12 ± 2.7 vs. 8.7 ± 2.2 cm 2 ) and smaller annular height (2.1 ± 0.8 vs. 4.3 ± 1.7 mm) than ischemic MR pts (all p<0.001). Although tenting volume was similar (2.8 ± 2.0 vs. 3.2 ± 1.6 ml, p=ns), tenting height was smaller in lone AF pts than ischemic MR pts (6.9 ± 3.2 vs. 9.0 ± 2.4 mm, p<0.05). CLc was smaller in lone AF pts than ischemic MR pts (3.1 ± 0.5, 3.5 ± 0.9 mm, p<0.05), whereas there were no differences in CLm and CLl between the two groups. Conclusion: 3D TEE clarified geometric differences in the mitral apparatus between ischemic MR and functional MR in lone AF pts.