[Right ventricular dysfunction of mitral valve stenosis].

Right ventricular function was studied in 9 patients with mitral valve stenosis who underwent mitral valve replacement (St. Jude Medical valve 29-31 mm) (MVR). The right ventricular systolic pressure/end-systolic volume index (RVSP/ESVI) correlated well with right ventricular ejection fraction (RVEF) in the normal control group thus it considered to be a index of right ventricular contractility. At rest, RVEF in the MVR group was significantly lower than that in the control group. However there was no difference in the RVSP/ESVI between both groups. In the MVR group, the total pulmonary resistance index (TPRI) and mean pulmonary arterial pressure (mPAP) were higher than those in the control group. During exercise, the RVSP/ESVI became higher in both groups, but RVEF did not increase in the MVR group. In the control group, RVEF became higher during exercise. In addition, TPRI and mPAP increased in the MVR group but the control group did not show significant changes during exercise. In conclusion, low RVEF after MVR, which reflects pump function of the right ventricle, was not caused by contractile dysfunction of the right ventricle but mainly by excess afterload due to irreversible pulmonary vascular resistance persisting after operation as a result of chronic pulmonary vascular hypertension.