Effect of cardiac tamponade on plasma concentrations of atrial natriuretic peptide (ANP) in calves

To study the effect of cardiac tamponade on plasma concentrations of atrial natriuretic peptide (ANP) female calves received an infusion of 450 ml of 0.9% saline into the pericardial space. The results indicate that an increase in intra-atrial pressure per se is not the decisive factor in the control of ANP secretion. Since atrial transmural pressure does not change during cardiac tamponade ANP concentrations are, as a rule, unaltered by that condition. An increase in plasma ANP is seen only during preshock hemodynamic conditions possible due to a reduced intra-atrial volume