EFFECTS OF LEFT-VENTRICULAR DIASTOLIC DYSFUNCTION ON EXERCISE CAPACITY 3 TO 6 WEEKS AFTER ACUTE MYOCARDIAL-INFARCTION IN MEN

To examine the effects of left ventricular (LV) diastolic dysfunction on exercise capacity, hemodynamic and radionuclide responses were meas ured at rest and during exercise in 50 patients with recent myocardial infarction. The ratio of an increase in pulmonary arterial wedge pres sure (PAWP) to an increase in LV end-diastolic volume (EDV) from rest to peak exercise (Delta PAWP/Delta EDV) wets used as an index of LV di astolic function. Delta PAWP/Delta EDV had modest and negative correla tions with peak oxygen consumption (VO2), cardiac output, and stroke v olume in all patients. Among patients with peak VO2 greater than or eq ual to 20 ml/min/kg (group I, n = 24) and those with peak VO2 <20 ml/m in/kg (group II, n = 26), there were no differences between the 2 grou ps with regard to resting LV ejection fraction, EDV, PAWP, cardiac out put, and stroke volume. Although there was no significant difference i n LV ejection fraction at peak exercise, group II had significantly re duced EDV, increased PAWP, and decreased cardiac output and stroke vol ume than those in group I. As a result, Delta PAWP/Delta EDV was signi ficantly higher in group II. These results suggest that LV diastolic d ysfunction has a key role in determining exercise capacity in patients with reduced exercise capacity after recent myocardial infarction.