Plasma and pericardial fluid natriuretic peptide levels in postinfarction ventricular dysfunction

Aims: In the present study we examined plasma and pericardial fluid ANP and BNP concentrations in postinfarction ventricular dysfunction. The association of peptide levels to left ventricular (LV) dysfunction and to the localization of the myocardial infarction (MI) was studied. Methods and results: Plasma and pericardial fluid samples were obtained from 37 patients undergoing coronary bypass surgery. According to the ECG and preceding coronary angiography, the patients were divided into three groups: previous anterior myocardial infarction (MI) (n = 12), previous inferior/posterior MI (n = 15) and no history of MI (n = 10). When compared to the control group with no MI, the patients with anterior MI had elevated plasma ANP and BNP (134 ± 13 vs. 81 ± 15 pg/ml, P < 0.01 and 95 ± 10 pg/ml vs. 26 ± 8 pg/ml, P < 0.01, respectively) and pericardial fluid BNP (473 ± 60 pg/ml vs. 57 ± 8 pg/ml, P < 0.001) levels. The plasma natriuretic peptide concentrations were not increased in the patients with inferior/posterior MI, but the pericardial fluid BNP concentrations were greater than in the patients with no history of MI (129 ± 35 pg/ml vs. 57 ± 8 pg/ml, P < 0.05). Six of the 12 patients with previous anterior MI had LVEF ≥ 45%. Despite their normal LV systolic function, these patients had increased plasma and pericardial fluid BNP levels when compared to the group with no history of MI (68 ± 18 pg/ml vs. 26 ± 8 pg/ml, P < 0.05 and 534 ± 258 pg/ml vs. 57 ± 8 pg/ml, P < 0.01, respectively). Conclusions: Previous anterior myocardial infarction was associated with increased cardiac BNP production even if the LV systolic function was normal (LVEF ≥ 45%). The high pericardial fluid BNP concentrations in postinfarction patients suggest that the BNP synthesis and release are augmented in the ventricular myocardium independent from the LVEF.