Geometric differences of the mitral apparatus between ischemic and dilated cardiomyopathy with significant mitral regurgitation

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, Aalpha; posterior, Palpha) were measured. In ICM-MR, Aa measured in the medial and central planes was significantly larger than that in the lateral plane (39+/-5degrees, 34+/-6degrees, and 27+/-5degrees, respectively; P<0.01), whereas Pα 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 Aalpha (38+/-8degrees, 37+/-9degrees, and 36+/-7degrees, P>0.05) and Pa (59+/-6degrees, 58+/-5degrees, and 57+/-6degrees, 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.