The mechanism of mitral regurgitation in dilated left ventricle.

To assess the mechanism of mitral regurgitation in ventricular dilatation, 24 patients with dilated cardiomyopathy (13 with and 11 without mitral regurgitation) and 10 normal individuals were studied by two-dimensional echocardiography. Left ventricular dimensions and mitral ring diameters in systole and diastole were measured in the long-axis section, and systolic interpapillary muscle distance in the short-axis section. The results showed: Mitral ring diameter is increased in most patients with dilated cardiomyopathy. Neither increased ring diameter, reduced ring contraction, nor decreased interpapillary muscle distance determine the presence of mitral regurgitation. The only difference between those patients with and without mitral regurgitation was the degree of left ventricular dilatation (p less than 0.05).