Haemodynamic, hormonal, and electrolyte effects of enalapril in heart failure.

Abstract

SUMMARY Enalapril, the new converting enzyme inhibitor, was administered to eight patients with heart failure (NYHA Functional Class II to IV) during standardised and intensive haemodynamic, hormone, and electrolyte monitoring. The first dose (5 mg) of enalapril induced a fall in plasma angiotensin II and noradrenaline levels, and prolonged decrements in systemic vascular resistance, arterial pressure, heart rate, and right heart pressures. Maximum haemodynamic effects were evident four to eight hours after the first dose, with return to baseline by 24 hours. Plasma angiotensin II levels, however, were still suppressed at 24 hours. The magnitude of haemodynamic response was related closely to baseline (pre-enalapril) activity of the renin-angiotensin system and the sympathetic system. Enalapril treatment over three days induced a positive cumulative balance of sodium and potassium, and a small increase in plasma potassium. Urine aldosterone excretion decreased in a stepwise fashion. Continued enalapril administration for four to eight weeks resulted in improved clinical status (NYHA Functional Class) and exercise tolerance in patients who initially were most severely incapacitated, but little change was observed in healthier subjects. We conclude that in heart failure, enalapril is a long acting converting enzyme inhibitor with clear cut beneficial haemodynamic effects in the short term. Long term controlled studies of enalapril in heart failure are warranted.

Acute and long‐term response to enalapril in congestive failure.

“…The pooled hypertension (Rich et al, 1982). The reduction ilts from the international pilot studies on in pulmonary resistance in the present study lapril in congestive heart failure ( Figure 8) was probably secondary to the marked reducroborate the favourable long-term haemo-tion in pulmonary capillary pressure, reducing amic effects obtained in the present and the extravascular fluid volume and the stiffness vious studies (Fitzpatrick et al, 1983; Levine of the lungs. Spurious reduction of the filling l., 1984).…”

Hemodynamic Effects of Benazeprilat in the Anesthetized Dog with Acute Left Ventricular Failure.

“…According to Cohn et al (15), vasodilators are effective not only in chronic heart failure but also in acute heart failure following myocardial infarc tion. Moreover, it was demonstrated that several ACE inhibitors were effective in ALVF induced in experimental animals by coronary embolization (4)(5)(6). Therefore, us ing a similar animal model of ALVF, we eval uated the action of benazeprilat, a new potent and long acting ACE inhibitor with no direct inotropic effect (7,11,16), on acute heart fail ure.…”

“…Several clinical studies have shown the efficacy of these agents in chronic (2,3) and acute car diac failure (4).…”

Enalapril in heart failure.

“…Full details of the protocol have been described before (Fitzpatrick et al, 1983). In brief a 2-day control period was followed by 3 days of enalapril therapy, 5, 10 and 20 mg given at 09.00 h on days 3, 4 and 5 respectively.…”

“…Enalapril has beneficial haemodynamic effects, at least in the short term (Fitzpatrick et al, 1983). Although information is available from studies in normal volunteers and essential hypertensives, little is known of drug levels and plasma converting enzyme activity in patients with heart failure during the introduction of enalapril.…”