EFFECTS OF EXERCISE ON LEFT-VENTRICULAR PERFORMANCE DETERMINED BY ECHOCARDIOGRAPHY IN CHRONIC, SEVERE MITRAL REGURGITATION SECONDARY TO MITRAL-VALVE PROLAPSE

Data on the effects of exercise on left ventricular (LV) volumes and e jection performance in patients with severe mitral regurgitation (MR) are limited. With use of a matched-pairs design, 10 asymptomatic patie nts with chronic, severe MR and normal LV systolic function who were n ot receiving vasodilator therapy (group 1) and 10 matched normal contr ol subjects no structural heart disease (group 2) performed symptom-li mited upright bicycle ergometry with quantitative echocardiographic an alysis. An additional 8 patients with severe, chronic MR and normal LY systolic function who were receiving vasodilator therapy at the time of testing (group 3) were studied for comparison. The 3 cohorts exerci sed for similar periods of time. Group 1 and 3 patients had similar en d-diastolic volumes at rest, both of which were significantly greater than those of normal controls. Although resting LV end-systolic volume was greater in groups 1 and 3 than in normal controls, the 3 groups h ad similar relative percent reductions in end-systolic volume during e xercise (30 +/- 12%, 32 +/- 13%, and 30 +/- 24%; p = NS). A similar pe rcent increase in LV ejection fraction was also observed in all 3 coho rts (18 +/- 9%, 15 +/- 9%, and 14 +/- 6%; p = NS). Forward stroke volu me increased significantly in group 1 (59 +/- 21 and 71 +/- 18 ml; p < 0.001) and in group 3 (59 +/- 17 and 68 +/- 13 ml; p < 0.05). Thus, i n asymptomatic patients with chronic, severe MR and normal LV ejection fraction at rest, there is an improvement in LV ejection fraction and an increase in forward stroke volume during exercise. These effects a re comparable to those observed in normal controls. Directional differ ences in the cohort receiving no active therapy were indistinguishable from either patients receiving vasodilator therapy or normal control subjects.