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[Vasodilator hormonal agents in chronic heart failure: effect of angiotensin-converting enzyme inhibitors]
1Departamento de Enfermedades Cardiovasculares, Universidad Católica de Chile.
Insights
Enalapril improved exercise capacity and heart function in patients with congestive heart failure (CHF). This angiotensin converting enzyme (ACE) inhibitor therapy reduced atrial natriuretic peptide (ANP) levels, a marker of poor prognosis in CHF.
Area of Science:
- Cardiology
- Pharmacology
Context:
- Congestive heart failure (CHF) involves abnormal neurohormonal activity.
- Angiotensin converting enzyme (ACE) inhibitors improve symptoms and survival in CHF.
- Limited data exists on ACE inhibition's effects on vasodilator and natriuretic hormones.
Purpose:
- To assess the chronic effects of enalapril on cardiac function and hormone levels in CHF patients.
- To evaluate enalapril's impact when added to digitalis and diuretics.
Summary:
- Nine patients with idiopathic dilated cardiomyopathy received enalapril (20 mg bid) for eight weeks.
- Measurements included left ventricular ejection fraction, functional class, atrial natriuretic factor, bradykinins, and urinary kalikreins/prostaglandin E2.
- Enalapril significantly increased maximal O2 consumption and LV ejection fraction.
Impact:
- Enalapril therapy led to significant reductions in plasma atrial natriuretic peptide (ANP) and urinary kalikreins.
- Decreased ANP levels may explain the sustained clinical benefits of ACE inhibitors in CHF.
- Findings highlight the role of ACE inhibitors in modulating neurohormonal imbalances in heart failure.
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.