RETURNYonago Acta medica 1992;35:151–166
Evaluation of Changes in Hemodynamics, Left Ventricular Function and Plasma Catecholamine Levels during Dynamic Exercise in Patients at Long Interval after Mitral Valve Replacement for Chronic Mitral Regurgitation
Md. Ejaj Ul Haque*†, Tohru Mori* and Hiroto Mashiba†
*Second Department of Surgery, and †First Department of Internal Medicine, Faculty of Medicine, Tottori University, Yonago 683, Japan
To assess the left ventricular (LV) function, hemodynamics and plasma catecholamine levels during dynamic exercise, 16 patients average 2.6 years after mitral valve replacement (MVR) for chronic mitral regurgitation (MR) and 5 control subjects were investigated by right heart catheterization and echocardiography during supine graded bicycle exercise. End-systolic LV dimension decreased and LV systolic function increased in both groups during exercise. Fractional shortening and mean velocity of circumferential fiber shortening were significantly lower in patients at rest (P < 0.05) and during exercise (P < 0.05) than control subjects. Mean pulmonary artery and pulmonary capillary wedge pressure during exercise were significantly higher in patients (both P < 0.05) than control subjects. Heart rate, systolic blood pressure and cardiac index increased significantly during exercise in both groups. Significantly greater rise in plasma norepinephrine (NE) was noted during exercise in patients than control subjects (rest: 244 ± 83 vs 166 ± 69 pg/mL, n.s.; peak exercise: 922 ± 690 vs 310 ± 83 pg/mL, P < 0.01). Plasma epinephrine (E) increased only in patients at peak exercise (P < 0.05), but the E levels were within normal values. Thus, these results showed that significantly reduced LV systolic function causes compensatory activation of sympathetic nervous system during exercise in patients at long interval after MVR for chronic MR.
Key words: exercise; hemodynamics; left ventricular function; plasma catecholamines