Geometric Differences of the Mitral Apparatus Between Ischemic and Dilated Cardiomyopathy With Significant Mitral Regurgitation: Real-Time Three-Dimensional Echocardiography Study

Background—This study was conducted to elucidate the geometric differences of the mitral apparatus in patients with significant mitral regurgitation caused by ischemic cardiomyopathy (ICM-MR) and by idiopathic dilated cardiomyopathy (DCM-MR) by use of real-time 3D echocardiography (RT3DE). Methods and Results—Twenty-six patients with ICM-MR caused by posterior infarction, 18 patients with DCM-MR, and 8 control subjects were studied. With the 3D software, commissure-commissure plane and 3 perpendicular anteroposterior (AP) planes were generated for imaging the medial, central, and lateral sides of the mitral valve (MV) during mid systole. In 3 AP planes, the angles between the annular plane and each leaflet (anterior, A&agr;; posterior, P&agr;) were measured. In ICM-MR, A&agr; measured in the medial and central planes was significantly larger than that in the lateral plane (39±5°, 34±6°, and 27±5°, respectively;P <0.01), whereas P&agr; showed no significant difference in any of the 3 AP planes (61±7°, 57±7°, and 56±7°, P >0.05). In DCM-MR, both A&agr; (38±8°, 37±9°, and 36±7°, P >0.05) and P&agr; (59±6°, 58±5°, and 57±6°, P >0.05) revealed no significant differences in the 3 planes. Conclusions—The pattern of MV deformation from the medial to the lateral side was asymmetrical in ICM-MR, whereas it was symmetrical in DCM-MR. RT3DE is a helpful tool for differentiating the geometry of the mitral apparatus between these 2 different types of functional mitral regurgitation.