Effects of short-term enalapril treatment on hemodynamic response to exercise in patients with congestive heart failure: A pilot study

This study was conducted to determine the effects of short-term enalapril treatment on left ventricular response to physical exercise in patients with congestive heart failure (CHF). The study followed a randomized, double-masked, placebo-controlled, crossover design. Twelve male patients (mean age, 52.8 ± 5.6 years; mean body weight, 75.6 ± 8.7 kg) with clinically documented CHF (left ventricular ejection fraction [EF] <40%; rang, 27% to 38%) were studied. Cardiac function was assessed during upright exercise, using an ambulatory randionuclide detector for continuous noninvasive monitoring of cardiac hemodynamics during baseline conditions and after 4 weeks of treatment with enalapril (20 mg daily, by mouth) or placebo. The heart rate response during enalapril treatment was comparable with that recorded during baseline conditions. On the contrary, during enalapril treatment, there was a statistically significant increase in left ventricular EF both at rest (34% ± 11%) and during peak exercise (31 ± 9%) when compared with baseline conditions (26% ± 10%, at rest; 23% ± 7%, during peak exercise). Similar changes were recorded for stroke volume (25% ± 5% end-diastolic volume [EDV] vs 35% ± 5% EDV and 27% ± 4% EDV vs 30% ± 5% EDV, at rest and during peak exercise, respectively) and cardiac output (20% ± 2% EDV/min vs 32% ± 5% EDV/min and 23% ± 4% EDV/min vs 42% ± 7% EDV/min, at rest and during peak exercise, respectively). When patients received placebo, left ventricular hemodynamic response to exercise was comparable with that observed during baseline conditions. These results suggest that enalapril has a favorable effect on left ventricular response to exercise in patients with CHF and indicate that noninvasive monitoring of left ventricular function may allow a reliable assessment of therapy.