Objective: This study determined whether alacepril treatment improves exercise hemodynamics in patients with heart failure.
Methods: Supine bicycle ergometer exercise was performed after administration of placebo and after acute and chronic (12 weeks) alacepril treatment in 4 patients with heart failure. Oxygen uptake (VO2), arterial oxygen saturation (SaO2), and mixed venous oxygen saturation (SvO2) were measured continuously using a pulse oxymeter and a fiber optic catheter. Cardiac index was calculated with Fick's equation.
Results: Acute alacepril treatment did not significantly alter the VO2 or hemodynamics. After chronic alacepril treatment, peak VO2 increased (placebo vs chronic alacepril treatment: 17.7 +/- 2.8 vs 21.7 +/- 2.8 ml/min/kg, p < 0.05). Arteriovenous oxygen difference (SaO2 - SvO2) at peak exercise was not altered, however, cardiac index at peak exercise (5.07 0.67 vs 6.35 +/- 0.48 I/min/m2, p = 0.02) increased and stroke volume index at peak exercise (37.3 +/- 3.4 vs 46.5 +/- 1.1 ml/m2, p = 0.07) tended to increase.
Conclusions: Chronic treatment with alacepril improved maximal exercise capacity in patients with heart failure. The increased peak VO2 was primarily due to the increased cardiac index, but not due to the widening of arteriovenous oxygen difference. Therapy-induced increase in stroke volume index may contribute to the increased cardiac index at peak exercise in our patients with heart failure.