Acute hemodynamic, hormonal and electrolyte effects of ramipril in severe congestive heart failure

The response to ramipril, 10 and 20 mg on consecutive days, in 9 patients with severe (New York Heart Association functional class III or IV) chronic congestive heart failure was measured. Hemodynamic cannulae were placed more than 2 days before ramipril administration to ensure a stable baseline. Dietary sodium (40 mmol daily) and potassium (80 mmol daily) were constant before and during the study, and maintenance doses of digoxin and furosemide (80 to 1,000 mg daily) were continued unchanged. Ramipril induced pronounced, sustained decreases in angiotensin converting enzyme activity, angiotensin II and aldosterone levels, and a reciprocal increase in plasma renin activity. Plasma catecholamines, antidiuretic hormone and cortisol levels were not altered. Urinary sodium and potassium excretion diminished, plasma sodium decreased and plasma potassium increased. Plasma urea and creatinine levels increased. Ramipril treatment resulted in a decrease in systemic arterial pressure that was sustained for 24 hours, a decrease in heart rate and an increase in cardiac index, but little change in pulmonary artery pressure or right atrial pressure. Three patients were drowsy after ramipril administration, and 1 patient had a marked, temporary reduction in urine output. It was concluded that ramipril is a potent, long-acting angiotensin converting-enzyme inhibitor that is likely to be beneficial in patients with severe cardiac failure.