EFFECT OF PERICARDIOCENTESIS ON CIRCULATING CONCENTRATIONS OF ATRIAL NATRIURETIC HORMONE AND ARGININE-VASOPRESSIN IN DOGS WITH SPONTANEOUS PERICARDIAL-EFFUSION

Factors regulating the secretion of atrial natriuretic hormone (ANH) a nd arginine vasopressin (AW) have not been elucidated fully. In severa l studies the release of these peptides has been studied by inducing b oth increased atrial pressure and atrial distension. A few studies emp loy cardiac tamponade, allowing the effect of atrial pressure and atri al stretch to be studied separately. In eleven dogs with spontaneous c ardiac tamponade the effect of pericardiocentesis on circulating conce ntrations of ANP and AVP was studied. Pericardiocentesis was followed by a prompt rise in (non-elevated) plasma ANH concentrations from 21.6 +/- 7.3 to 65.4 +/- 17.1 pmol/l (mean +/- SEM). The initially slightl y elevated AVP concentration of 5.5 +/- 1.5 pmol/l declined following pericardiocentesis to 2.1 +/- 0.5 pmol/l. In three dogs the systolic a rterial pressure was measured indirectly and the central venous pressu re was measured with a fluid-filled catheter. Before and after pericar diocentesis arterial pressure readings did not change significantly. C entral venous pressure values showed an immediate very steep significa nt decrease after centesis. It is concluded that ANH release is primar ily regulated by stretch and not by atrial pressure, that plasma AW co ncentrations are moderately elevated in cardiac tamponade and that in cardiac tamponade pericardiocentesis causes a rapid decline in plasma AVP concentration.