Plasma concentrations of alpha-human atrial natriuretic polypeptide and cyclic GMP in patients with heart disease.

Plasma concentrations of immunoreactive alpha-human atrial natriuretic polypeptide (i alpha-hANP) and cyclic guanosine monophosphate (cGMP) were measured in 70 patients with heart disease. Plasma concentrations of i alpha-hANP were directly related to the severity of heart disease (F = 29.61, p less than 0.001). Plasma concentrations of i alpha-hANP were well correlated with pulmonary capillary wedge pressure (PCWP; r = 0.64, p less than 0.001), mean pulmonary arterial pressure (PAP; r = 0.62, p less than 0.001), and mean right atrial pressure (RAP; r = 0.75, p less than 0.001). Plasma concentrations of cGMP were also directly related to the severity of heart disease (F = 13.61, p less than 0.001) and highly correlated with plasma concentrations of i alpha-hANP (r = 0.73, p less than 0.001). Plasma concentrations of cGMP were also closely correlated with PCWP (r = 0.69, p less than 0.001), mean PAP (r = 0.61, p less than 0.001), and mean RAP (r = 0.60, p less than 0.001). The i alpha-hANP concentrations of plasma samples obtained from the coronary sinus were approximately fourfold higher than those of samples obtained from the pulmonary artery, whereas cGMP concentrations were comparable in plasma samples obtained from either site. Elevation of cGMP concentrations following intravenous infusion of synthetic alpha-hANP was comparable in plasma samples obtained from the coronary sinus and the pulmonary artery. These findings suggest that elevated plasma concentrations of i alpha-hANP in cardiac patients result from an increase in the secretion of ANPs, which is probably accelerated by elevation of right or left atrial pressure, and that plasma concentrations of cGMP reflect circulating levels of alpha-hANP.