Atrial natriuretic peptide during acute treatment of congestive heart failure

Summary. Atrial natriuretic peptide (ANP) induces potent diuretic/natriuretic, vasorelaxing and aldosterone inhibitory effects. Increased plasma levels in congestive heart failure (CHF) have been reported. The aim of this study was to investigate plasma immunoreactive ANP (ir-ANP) levels during acute treatment of CHF. Seven patients with CHF underwent cardiac catheterization. Ir-ANP plasma levels were followed up to two h after administration of an orally given phosphodiesterase inhibitor (Milrinone); a substance with positive inotropic and peripheral vasodilating properties. In all patients cardiac output increased and cardiac filling pressures decreased markedly. Initially high ir-ANP plasma levels decreased. Our patients did not have an increased blood volume. It is concluded that plasma ir-ANP levels in the pulmonary artery rapidly decrease when atrial pressure is reduced. These data suggest that atrial pressure is the major determinant for release of ir-ANP in man and that the ability to respond quickly to changes in cardiac filling pressures is maintained in patients with severe CHF. Plasma ir-ANP levels may also become useful as an index of the degree of heart failure and serve as a tool in monitoring response to drug therapy.