Abstract
The functional and morphological changes in the left ventricle were assessed in 43 patients with mitral stenosis (MS) using echocardiography. The MS patient group consisted of 24 patients with sinus rhythm and 23 with atrial fibrillation. The cardiac functions of the patients were from I to III according to the New York Heart Association (NYHA) classification. The control group included 14 normal subjects and 3 with lone atrial fibrillation. The left ventricular ejection fractions (EF) at rest and in response to a bicycle ergometer (10 watts for 3 min) were examined by echocardiography. Comparison of the EF by echocardiography to the index by radionuclide angiography proved the efficacy of echocardiography for estimating LV function in patients with MS. Morphological changes in the left ventricle were caused by submitral lesions. These changes were quantitatively represented by a deformity ratio (DR). The EF at rest in the MS patients with atrial fibrillation was lower than in the remaining groups, and the MS patients with sinus rhythm showed an EF similar to that of normal subjects and lone atrial fibrillation patients. Some of the MS patients with atrial fibrillation had a higher EF while others had a lower EF. After exercise, the EF of the MS patients with sinus rhythm, who had NYHA class III cardiac function, decreased due to reduction of left ventricular end-diastolic dimension (LVDd) caused by an increased heart rate (HR) and total peripheral resistance (TPR). EFs of the remaining subjects were augmented after exercise. The relationships between the resting EF and other hemodynamic parameters measured were investigated to verify which factors influence left ventricular function in MS patients. There were no significant relationships between EF and mitral valve area (MVA), LVDd, HR or TPR. However, the DR closely correlated to the EF with a correlation coefficient of -0.75. Surgical treatment of the mitral valve improved both the cardiac function as to the NYHA class and the EF at rest, along with significant recovery of the DR. The percent change in the EF varied inversely with that in the DR (correlation coefficient, -0.57). Response of the EF to exercise was also improved after surgery. Therefore, it is concluded that left ventricular deformities of patients with MS induced by subvalvular lesion limits the left ventricular function and causes a lower EF.
