Echocardiographic assessment of left ventricular function in mitral valve disease.

Echocardiography was used to study left ventricular size and contraction in 90 patients with isolated mitral valve disease--47 patients with mitral stenosis, 26 with mixed mitral valve disease and 89 with mitral regurgitation. Left ventricular measurements included the end-diastolic internal dimension (LVIDd), mural thickness (PWTd), an index of circumferential myocardial contraction--fractional shortening (see article)--and stroke volume (LVSV). The left ventricle was abnormally small only when mitral stenosis was severe. Reduced myocardial contraction was common in patients with rheumatic valvular heart disease but was rarely severe. In mitral regurgitation without left ventricular failure, measurements were characteristic of volume overload with increases in LVIDd, LVSV and PWTd which were related to the severity of regurgitation. In other diseases, left ventricular failure is usually associated with reduced myocardial contraction (FS) but in mitral regurgitation with failure, myocardial contraction (FS 32%) did not differ significantly from normal (34%). The reduction in afterload caused by mitral regurgitation probably increases myocardial contraction and may lead to underestimation of the severity of myocardial impairment. Also potentially misleading was severe mitral regurgitation with normal values for LVIDd and LVSV (three patients). When the distinction between cardiomyopathy with secondary mitral regurgitation and primary mitral regurgitation was difficult clinically, echocardiography could usually make the distinction by demonstrating severe reduction of myocardial contraction with a slight or moderate increase in LVSV.