[Impaired left ventricular systolic function in mitral stenosis].

OBJECTIVES: Left ventricular dysfunction is known in patients with mitral stenosis, but the incidence and cause remain unclear. The incidence and the factors related to left ventricular dysfunction were investigated in strictly selected patients with isolated mitral stenosis. METHODS: This study investigated 33 patients (5 males, 28 females) with isolated mitral stenosis aged 56 +/- 9 years. Left atrial dimension, left ventricular diastolic and systolic dimensions, mitral valve area, and mean transmitral pressure gradient were measured by echocardiography. Left ventricular ejection fraction was measured by Simpson's method. Patients were divided into two groups according to the ejection fraction (< 50%, > or = 50%). RESULTS: Seven patients (21%) had decreased left ventricular contraction and 26(79%) had normal contraction. The incidence of patients with atrial fibrillation in the low ejection fraction group was significantly higher than in the normal ejection fraction group(86% vs 31%, p < 0.01). There were no significant differences in the severity of mitral stenosis or other echocardiographic indices between the two groups. CONCLUSIONS: Low ejection fraction was present in 21% of patients with mitral stenosis. Since atrial fibrillation was more common in patients with low ejection fraction than those with normal ejection fraction, the rhythm disturbance may be related to the decreased left ventricular contraction.