Plasma Concentration of Atrial Natriuretic Polypeptide in Patients with Atrial Tachycardia

Abstract

To investigate the mechanisms of polyuria associated with tachycardia, we measured plasma concentrations of α-human atrial natriuretic polypeptide (α-hANP) and cGMP in 6 patients with paroxysmal tachycardia. Plasma concentrations of immunoreactive α-hANP and cGMP increased by +69% (p<0.05) and +100% (p<0.05), respectively, during both paroxysmal atrial tachycardia and atrial fibrillation. To examine whether tachycardia per se raises the secretion of α-hANP, we also determined plasma concentrations of α-hANP and cGMP in 5 patients during rapid atrial pacing. The pacing-induced tachycardia also increased both of the plasma concentrations. Further, the examinations of cardiac and renal functions in patients with complete atrioventricular block during rapid pacing revealed that each of the increases in atrial pressures, urinary sodium excretion and creatinine clearance were in parallel with the change in plasma concentration of α-hANP. These results suggest that an increase in plasma concentration of α-hANP during paroxysmal tachycardia is mainly due to elevation of atrial pressure and that this increase in α-hANP contributes to tachycardia polyuria.