Effect of pericardiocentesis on plasma levels of brain natriuretic peptide in cardiac tamponade

Brain natriuretic peptide (BNP) is a new natriuretic peptide with marked similarity to atrial natriuretic peptide (ANP) in both its amino acid sequence and its biological actions.1 Although originally isolated from the porcine brain, subsequent studies in pigs, rats and humans have shown that BNP is also a cardiac hormone synthesized and secreted from the heart into the circulation.2 The stimulus for BNP release in humans is unclear, although plasma levels of human BNP-like immunoreactivity have been reported to be increased in classical conditions of volume overload, such as congestive heart failure.2 Therefore, it is likely that the release of BNP may be related to an increase in either cardiac pressure or distension. With regard to ANP, there is compelling evidence that atrial distension is the primary stimulus for its release based on observations in patients with cardiac tamponade.3 Relief of tamponade by aspiration results in a reduction in atrial pressure, but an increase in both atrial distension and plasma ANP concentration. Therefore, we compared the plasma concentrations of human BNP-like immunoreactivity and ANP during therapeutic pericardiocentesis in patients with cardiac tamponade.