AUGMENTED SECRETION OF ATRIAL AND BRAIN NATRIURETIC PEPTIDES DURING DYNAMIC EXERCISE IN PATIENTS WITH OLD MYOCARDIAL-INFARCTION

To assess the role of atrial and brain natriuretic peptides (ANP, BNP) in maintaining cardiac performance at rest and during exercise in pat ients with cardiac dysfunction, we measured plasma levels of ANP and B NP during Tl-201 dynamic exercise testing in 32 patients with angiogra phically proven old myocardial infarction (OMI) and 35 normal control subjects (CS). Plasma levels of ANP and BNP at rest were significantly higher in patients with OMI than in CS (ANP, 42.6+/-19.3 vs 19.4+/-2. 4 pg/ml, p<0.01; BNP, 53.4+/-32.5 vs 2.8+/-0.8 pg/ml, p<0.01, respecti vely). Correlations were found between plasma levels of these peptides and left ventricular ejection fraction (LVEF), cardiac index (CI), pu lmonary capillary wedge pressure (PCWP) and left ventricular end-diast olic pressure (LVEDP) in patients with OMI. In addition, a strong posi tive correlation was found between plasma levels of these peptides and the severity score obtained from Tl-201 myocardial scintigraphy. Duri ng exercise, both ANP and BNP significantly increased in patients with OMI. However, in CS, although ANP increased, BNP remained unchanged. The changes in plasma levels of ANP or BNP from at rest to peak exerci se correlated with LVEF, CI, PCWP, LVEDP and the severity score in pat ients with OMI. These findings indicate that ANP and BNP play an impor tant role in maintaining cardiac performance at rest and during exerci se in patients with cardiac dysfunction.