LEFT-VENTRICULAR SYSTOLIC AND DIASTOLIC FUNCTION, AND EXERCISE CAPACITY 6 TO 8 WEEKS AFTER ACUTE MYOCARDIAL-INFARCTION

Echocardiographic and Doppler-derived measurements of left ventricular (LV) function at rest were examined as predictors of maximal bicycle exercise capacity in a homogeneous group of 115 patients with mild to moderate LV dysfunction (ejection fraction 22 to 56%, median 43%) part icipating in the DEFIANT study of nisoldipine after acute myocardial i nfarction. Although the relations were not exact, peak exercise work l oad 7 weeks after infarction correlated with measurements of diastolic LV function at rest. Exercise work load was inversely related to peak late diastolic transmitral blood flow velocity (A wave) (slope -86.6; 95% confidence interval -120.9 to -52.2) and directly to the E/A rati o (slope 20.5; 95% confidence interval 6.0 to 35.1). The relations bet ween exercise work load and peak late diastolic flow velocity remained significant after correction for age, sex, heart rate at rest, and us e of beta-blocking drugs or nisoldipine. There was no relation between peak exercise work load and peak early diastolic transmitral flow vel ocity (E wave), isovolumic relaxation period or deceleration time. Mea surements of systolic LV function (LV end-diastolic and end-systolic v olumes, and ejection fraction, stroke volume and cardiac index) were a lso not significant as predictors of exercise capacity.