Sympathetic responses to atrial natriuretic peptide in patients with congestive heart failure

Previous studies have shown that atrial natriuretic peptide (ANP) has relat ive sympathoinhibitory effects that are of potential benefit in patients wi th congestive heart failure (CHF). In this study, cardiac and systemic symp athetic responses to ANP were evaluated and compared with responses to sodi um nitroprusside (SNP) in patients with CHF. Right- and left-heart hemodyna mics were obtained simultaneously with cardiac (CANESP) and total body (TBN ESP) norepinephrine spillover; these were measured by using the radiotracer technique. Reductions in arterial blood pressure and cardiac filling press ures were similar with both drugs. ANP and SNP caused a significant and sim ilar increase in TBNESP. Mean values for CANESP did not change in either gr oup, but the response of individual patients was dependent on the effect on diastolic blood pressure (r = -0.71, p < 0.01). These results do not provi de evidence for a sympathoinhibitory effect of ANP, but suggest that in pat ients with CHF, cardiac sympathoexcitatory response to arterial barorecepto r unloading may be countered by a potential sympathoinhibitory effect cause d by a reduction in cardiac filling pressures. In the setting of CHF, vasod ilator therapy may decrease cardiac sympathetic activity if systemic hypote nsion is avoided.