Atrial natriuretic peptide release responds to atrial stretch and not to atrial pressure: observations during pericardiocentesis in a young woman.

The effect of pericardiocentesis on the plasma concentration of atrial natriuretic peptide was studied in a patient with cardiac tamponade. Plasma atrial natriuretic peptide concentrations rose sharply from 42 pmol l-1 to a maximum of 150 pmol l-1 with a corresponding fall in mean right atrial pressure from 20 mmHg to 6 mmHg. Our results suggest that atrial 'stretch' (or transmural pressure) rather than atrial pressure per se, is the primary stimulus for atrial natriuretic peptide release in man.