Hemodynamic, hormonal, and renal effects of atrial natriuretic peptide in untreated congestive cardiac failure.

We report the effects of intravenous infusion of the atrial natriuretic peptide analogue, met-ANP-26 (2 micrograms/min for 2 to 4 hours), in four patients with cardiomyopathy and severe congestive cardiac failure who had not received any previous cardiac therapy. The average cardiac index before infusion was 1.8 L/min/m2. Severe sodium and water retention was confirmed by high levels of total body water and extracellular liquid, whereas renal blood flow and glomerular filtration rate were reduced. Plasma concentration of ANP, norepinephrine, cortisol, and growth hormone were significantly increased before infusion. The infusion had no significant hemodynamic effect. After 2 hours urine volume had increased significantly from 51 to 76 ml/hr, urinary concentration of sodium from 72 to 90 mmol/L, and sodium excretion from 4.5 to 8.2 mmol/hr. The infusion was accompanied by a significant increase in plasma ir-ANP from 193 to 980 pg/ml. There were no significant effects on the plasma concentrations of norepinephrine, epinephrine, aldosterone, vasopressin, cortisol, growth hormone, or prolactin and no significant change in plasma renin activity. After 2 hours of infusion one patient had a severe sinus tachycardia and another had a sinus bradycardia. Both arrhythmias disappeared without harmful effects soon after the infusion was stopped.