Six weeks of enalapril treatment (10-20 mg/day) reduced myocardial overflow of noradrenaline at peak exercise and lowered cardiac workload compared to placebo in men with congestive heart failure.
RCT (n=14)
Double-blind
Does enalapril reduce myocardial noradrenaline overflow during exercise in men with congestive heart failure?
Long-term enalapril therapy reduces myocardial sympathetic activity and cardiac workload during exercise in patients with chronic heart failure.
The effects of the angiotensin converting enzyme inhibitor enalapril on myocardial sympathetic tone, as represented by noradrenaline overflow, were studied in 14 men with congestive heart failure (mean ejection fraction 20%) in a double blind crossover comparison with placebo. Arterial and coronary sinus catecholamine concentrations and oxygen content, and coronary sinus blood flow, were measured at rest and during peak symptom limited upright exercise on a bicycle ergometer. There were no significant changes four hours after the first dose of enalapril, but after six weeks of treatment (10-20 mg/day) enalapril reduced myocardial overflow of noradrenaline at peak exercise. The external workload (exercise duration) increased from baseline values after both placebo and enalapril, and there was no difference between placebo and enalapril at six weeks. Heart work, however, was lower after enalapril: stroke work index was reduced at rest and the double product was lower at peak exercise. The reduction in maximal myocardial oxygen consumption after enalapril did not reach statistical significance. Coronary sinus adrenaline concentrations after enalapril and after placebo were not significantly different. The long term reduction of myocardial sympathetic activity on exercise may represent a significant benefit from angiotensin converting enzyme inhibition in heart failure and may reflect a reduced cardiac workload.
Mulligan et al. (1989) conducted an RCT in Congestive heart failure (n=14). Enalapril vs. Placebo was evaluated on Myocardial overflow of noradrenaline at peak exercise. Six weeks of enalapril treatment (10-20 mg/day) reduced myocardial overflow of noradrenaline at peak exercise and lowered cardiac workload compared to placebo in men with congestive heart failure.