Right ventricular performance in mitral stenosis.

Until recently, the dynamic geometry and pump function of the pressure-overloaded right ventricle in patients with mitral stenosis and pulmonary hypertension had not been well defined. With use of a recently developed method for calculating right ventricular volume in human beings, seven normal subjects and eight patients with mitral stenosis and pulmonary hypertension had right ventricular performance assessed from computer-analyzed biplane right ventriculograms. Patients with mitral stenosis has elevated values for systolic right ventricular pressure (mean +/- standard error of the mean 25 +/- 2 for normal subjects, 57 +/- 6 mm Hg for patients with mitral stenosis), but normal values for right ventricular end-diastolic volume index (normal 95 +/- 11, patients 81 +/- 9 ml/m2) and ejection fraction (normal 0.49 +/- 0.02, patients 0.58 +/- 0.04). Comparison of right ventricular function using group performance curves of stroke work versus end-diastolic volume revealed the slope of the mitral stenosis line to be significantly greater than the normal line. A plot of right ventricular stroke volume versus end-diastolic volume, which removes pressure from the performance index, revealed that the two groups have similar performance. Left ventricular function measured by ejection fraction was reduced in mitral stenosis. These data suggest that the right ventricle performs normally in patients with mitral stenosis with moderate pulmonary hypertension and maintains normal size and ejection fraction.