Systolic and diastolic properties of the human left ventricle during valve replacement for chronic mitral regurgitation.

ABSTRACT

M mode and two dimensional echocardiography were combined with pressure-flow data to analyze systolic mechanics and diastolic compliance in nine patients during valve replacement for chronic mitral regurgitation. Both M mode (six patients) and two dimensional (four patients) echographic analyses revealed large decreases in early postoperative shortening fraction (-24 +/- 17 [standard deviation] percent M mode study, p < 0.01 -30 +/- 12 percent two dimensional study, p < 0.02), which were significantly different from small changes observed in control subjects (M mode study, +7 +/- 10 percent, 25 subjects and two dimensional study, -7 +/- 14 percent, 8 subjects). Additional data suggest that ventricular compliance is increased in chronic mitral regurgitation and that elimination of the low impedance left atrial pathway by valve replacement is associated with a significant increase in wall stress (five patients, p < 0.02) that appears to be responsible for the decreased ejection fraction postoperatively. Analysis of hemodynamic variables other than ejection fraction and rate of circumferential shortening revealed no difference between five postoperative patients with chronic mitral regurgitation and five with coronary artery disease. These results in human subjects confirm predictions from studies in animal models and suggest that unique properties of chronic mitral regurgitation and demand special attention when patients with this condition are being evaluated for surgery.