Atrial and brain natriuretic peptide response to exercise in patients with ischaemic heart disease

1. The response of venous plasma natriuretic peptides (atrial natriuretic peptide, ANP, and brain natriuretic peptide, BNP) plasma cyclic guanosine monophosphate (cGMP) and vasoactive hormones to dynamic exercise has been studied in 16 subjects undergoing diagnostic exercise tolerance for ischaemic heart disease (IHD), and in five healthy control subjects. 2. In patients with IHD, plasma ANP increased 3-fold (mean 16 +/- 2.5 pmol/L pre-exercise, 51 +/- 11 pmol/L after exercise, P < 0.01). Increase in plasma BNP (10.5 +/- 1.6 pmol/L pre-exercise, 13 +/- 2 pmol/L after exercise, P < 0.01) was proportionately much less than ANP but more sustained. In exercising normal subjects, plasma ANP levels doubled (P < 0.01) but there was no significant change in plasma BNP levels. 3. In patients with IHD, there was a significant correlation between levels of plasma ANP and BNP before exercise (r = 0.97, P < 0.001) as well as during exercise (r = 0.79, P < 0.001). 4. Hormone responses in patients with positive exercise tests did not differ significantly from those with negative tests. 5. Although resting levels of plasma ANP and BNP in IHD are correlated, the findings indicate different mechanisms of secretion. The low BNP/ANP ratio in response to acute dynamic exercise presumably reflects the predominance of ANP in pre-secretory atrial stores.