Correlation between atrial natriuretic peptide and baroreflex sensitivity in patients with congestive heart failure

The aim of this study was to investigate the relationship between baroreflex sensitivity (BRS) and humoral factors in patients with congestive heart failure (CHF). BRS was assessed by the phenylephrine method in 16 patients with CHF and in 13 healthy controls. The CHF group was subdivided into 2 groups according to BRS (group A: <6 ms/mmHg, n=9; group B: > or =6 ms/mmHg, n=7). BRS was markedly depressed in CHF than in the controls (4.8+/-2.0 vs 8.3+/-3.6 ms/mmHg, p<0.01), and lower in group A than group B (3.3+/-1.3 vs 6.7+/-0.6 ms/mmHg, p<0.01). The plasma human atrial natriuretic peptide (h-ANP) level in group A was significantly higher than in group B (54.6+/-27.6 vs 18.0+/-7.4 pg/ml, p<0.01), and a significant inverse correlation was observed between plasma h-ANP and BRS (r=-0.635, p<0.01). However, there were no significant differences between the 2 groups in plasma catecholamine concentration, plasma renin activity and cardiac function by echocardiogram. These findings suggest that the elevation of endogenous ANP may also serve to compensate for impaired BRS in patients with CHF, in addition to its principal actions, such as diuresis and vasodilation.