[Vasodilator hormonal agents in chronic heart failure: effect of angiotensin-converting enzyme inhibitors]. / Hormonas vasodilatadoras en la insuficiencia cardíaca crónica: efecto de la inhibición de la enzima convertidora de angiotensina.

BACKGROUND: Administration of angiotensin converting enzyme (ACE) inhibitors to patients with congestive heart failure (CHF) is associated to a decrease in the abnormal vasoconstrictor neurohormonal activity. This contributes to the sustained benefits of these drugs on symptoms and survival of patients with CHF. There is little information, however, regarding the effects of ACE inhibition on vasodilator and natriuretic hormones. AIM: To evaluate the chronic effects of enalapril, in addition to digitalis and diuretics in patients with chronic cardiac failure. PATIENTS AND METHODS: Nine patients with an idiopathic dilated cardiomyopathy (8 male, aged 48 to 76 years old) under treatment with digitalis and diuretics, received enalapril 20 mg bid during eight weeks. Before and after this treatment period resting left ventricular ejection fraction, functional class, plasma levels of atrial natriuretic factor and bradykinins (BK) and urinary excretion of kalikreins (BK) and prostaglandin E2 (PGE2) were measured. RESULTS: After enalapril therapy, there was a significant increase in maximal O2 consumption (14.8 +/- 1.2 to 18.6 +/- 1.5 ml/kg/min, p < 0.05) and radionuclide LV ejection fraction (27.4 +/- 1.1 to 31.4 +/- 0.9% p < 0.05). This was associated with a significant decrease in plasma ANP levels (559 +/- 158 to 178 +/- 54.8 pg/ml) and UK (391 +/- 112 to 243 +/- 92 Cu/24 h). CONCLUSIONS: The decrease in ANP levels, which is a well known marker of prognosis in CHF, could contribute to explain the sustained clinical benefits observed with ACE inhibitors in patients with CHF.