[Right ventricular function in patients with rheumatic mitral valve stenosis. Effect of balloon mitral valvuloplasty]

Postrheumatic mitral stenosis might cause impairment of right ventricular (RV) function due to both an increase in RV afterload and rheumatic myocardial disease. Therefore, we investigated in 19 patients with postrheumatic mitral stenosis and sinus rhythm right ventricular volumes and hemodynamics by a computerized thermodilution catheter during rest and supine bicycle exercise. In 14 patients the investigation was repeated within 2 days after balloon mitral valvuloplasty. Resting RV ejection fraction was decreased (43 (15-53)%, median (range)) and correlated significantly with RV end-systolic volume index (r = -0.90), stroke volume index (r = 0.77), RV end-diastolic volume index (r = -0.76), heart rate (r = -0.69), pulmonary artery resistance (r = -0.69), and mean pulmonary artery pressure (r = -0.68). RV end-diastolic volume index was 107 (81-200) ml/m2. Exercise induced a decrease of RV ejection fraction to 36 (13-48)% at 50 Watt (p < 0.001), while it increased RV end-diastolic volume index to 131 (78-231) ml/m2 (p < 0.001). Balloon mitral valvuloplasty improved RV ejection fraction at rest from 41 (15-47)% to 48 (39-55)% (p < 0.005) and from 30 (13-46)% to 43 (27-56)% during exercise (p < 0.005). The increase of RV ejection fraction after valvuloplasty was caused by an increase in stroke volume, but not by a reduction in RV end-diastolic volume.

Depending on the increased RV afterload, RV function is markedly depressed in mitral stenosis. An immediate and almost complete improvement of RV function occurs with the reduction of RV afterload after balloon mitral valvuloplasty.(ABSTRACT TRUNCATED AT 250 WORDS)