Abnormal Left Ventricular Contraction in Patients with Mitral Stenosis

Abstract

Twenty-five patients with pure mitral stenosis and nine normal subjects were studied by selective left ventricular cineangiocardiography. Left ventricular volumes were measured at end systole, throughout diastole, and at end diastole. Although filling curves showed that the left ventricles filled slowly in patients with mitral stenosis, normal end-diastolic volumes were attained provided diastole lasted 400 msec. Despite normal end-diastolic volumes, end-systolic volumes were significantly larger ( P < 0.0005) in the patients with mitral stenosis (av=64.6 ml) than in normal subjects (30.8 ml). Correspondingly, left ventricular ejection fractions were significantly lower ( P < 0.0005) in the patients with mitral stenosis (55.7%) than in the normal subjects (76.7%). Qualitative analysis of the cineangiocardiograms demonstrated that 20 patients with mitral stenosis had distortion, immobility, and rigidity of the posterobasal area of the left ventricle. It is hypothesized that a rigid "mitral complex" immobilizes the posterobasal area of the left ventricle in patients with mitral stenosis, thereby impairing left ventricular contraction, and that this impairment is an important factor in the reduced cardiac output of these patients.