Increased levels of beta-human atrial natriuretic peptide-like immunoreactivity in chronically overloaded atrial...

The levels and molecular form of atrial natriuretic peptide-like immunoreactivity (ANP-LI) in human atrial tissue were investigated. The levels of right atrial ANP-LI were significantly higher in mitral disease than in other cardiac or noncardiac diseases. The increased ANP-LI was mainly accounted for by an increase in beta-human ANP-LI (beta-hANP-LI). Both total ANP-LI and beta-hANP-LI levels were associated with the presence of atrial fibrillation and with increased atrial pressure. Plasma beta-hANP-LI levels were also increased in mitral disease. These results suggest that human atrium with hemodynamic overloads is characterized by increased tissue levels of ANP and by a shift to the beta-hANP form.