The roles of natriuretic peptides in pericardial fluid in patients with heart failure.

Background: It is well known that the plasma concentrations of atrial and brain natriuretic peptides, as cardiac hormones, are elevated in heart failure.

Hypothesis: Pericardial fluid in patients with various heart diseases contains both natriuretic peptides that are released into the pericardial fluid. However, it is unknown whether these peptides reflect cardiac function in patients with various heart diseases, more than both the peptides in blood.

Methods: Plasma and pericardial fluid samples were obtained from 22 patients undergoing cardiac surgery for the measurement of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels in plasma and pericardial fluid.

Results: The ANP levels in pericardial fluid were higher in patients with impaired left ventricular systolic function (ejection fraction<50% versus>or=50%; 77.0+/-4.9 versus 14.0+/-50.9, p=0.017), but not BNP.However, BNP levels in pericardial fluid were significantly higher in patients with left ventricle dilatation (left ventricular diastolic dimension54 mm; 130.3+/-68.9: 709.7+/-324.7, p=0.0168). Moreover, BNP levels in pericardial fluid were significantly higher in Grade III than Grade II and I (Grade I: echo-free space<5 mm, Grade II: 5-10 mm, Grade III: >10 mm).

Conclusion: These results suggest that BNP levels in pericardial fluid served as more sensitive and accurate indicators of left ventricular diastolic dysfunction, and that increased BNP levels in pericardial fluid may have an important pathophysiologic role in heart failure as a cardiocyte-derived antifibrotic factor.