Effects of left ventricular diastolic dysfunction on exercise capacity three to six weeks after acute myocardial infarction in men

Abstract

To examine the effects of left ventricular (LV) diastolic dysfunction on exercise capacity, hemodynamic and radionuclide responses were measured at rest and during exercise in 50 patients with recent myocardial infarction. The ratio of on increase in pulmonary arterial wedge pressure (PAWP) to an increase in LV end-diastolic volume (EDV) from rest to peak exercise (ΔPAWP/ΔDV) was used as an index of LV diastolic function. ΔPAWP/ΔEDV had modest and negative correlations with peak oxygen consumption (VO 2), cardiac output, and stroke volume in all patients. Among patients with peak VO 2 ≥20 ml/min/kg (group I, n = 24) and those with peak VO 2 <20 ml/min/kg (group II, n = 26), there were no differences between the 2 groups with regard to resting LV ejection fraction, EDV, PAWP, cardiac output, and stroke volume. Although there was no significant difference in LV ejection fraction at peak exercise, group II hod significantly reduced EDV, increased PAWP, and decreased cardiac output and stroke volume than those in group I. As a result, ΔPAWP/ΔEDV was significantly higher in group II. These results suggest that LV diastolic dysfunction has a key role in determining exercise capacity in patients with reduced exercise capacity after recent myocardial infarction.