Yonago Acta medica 1992;35:79–90

Comparative Assessment of Left Ventricular Function and Hemodynamics during Supine Bicycle Exercise In Patients before and after Mitral Valve Replacement for Chronic Mitral Regurgitation

Md. Ejaj ul Haque, Seiichiro Sasaki and Hiroto Mashiba*

Second Department of Surgery and *First Department of Internal Medicine, Faculty of Medicine, Tottori University, Yonago 683, Japan

We studied 5 patients before and after mitral valve replacement (MVR) for chronic mitral regurgitation (MR) and 5 control subjects. All were evaluated by echocardiography and right heart catheterization during supine bicycle exercise. Left ventricular (LV) end-systolic dimension decreased and LV systolic function (fractional shortening and mean velocity of circumferential fiber shortening) increased significantly during exercise in patients before and after MVR and in control subjects. LV systolic function after MVR was significantly lower at rest and during exercise than before MVR (both P < 0.05). At peak exercise, cardiae index (CI) was significantly higher in patients after MVR than before MVR (rest: 2.5 ± 0.3 vs 2.4 ± 0.7 L/min/m2, NS; peak exercise: 5.3 ± 0.4 vs 4.1 ± 1.0 L/min/m2, P < 0.05). No significant differences in mean pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure (PCWP) were noted between the patients before and after MVR. Responses of LV function and hemodynamics to exercise were not altered after valve replacement. Thus, it is concluded that MVR resulted in improvement of hemodynamic function by significantly greater rise of CI at peak exercise. But LV systolic function decreased significantly due to the reason that the myocardial dysfunction was concealed before MVR by favorable loading conditions.

Key words: exercise; hemodynamics; left ventricular function; mitral regurgitation

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