Improvement in left ventricular function in response to carvedilol is accompanied by attenuation of neurohumoral activation in patients with dilated cardiomyopathy

Background: We sought to evaluate whether improvement in ejection fraction (EF) with carvedilol therapy is accompanied by improvement in neurohumoral factors. Methods and Results: Forty-two patients with dilated cardiomyopathy were given carvedilol for 3 to 5 months. Changes in EF, plasma atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and norepinephrine levels were determined. Iodine-123 metaiodobenzylguanidine (MIBG) images were also obtained before and after carvedilol therapy. Myocardial uptake of MIBG was calculated as the heart to mediastinal activity ratio (H/M). Storage and release of MIBG was calculated as percent myocardial MIBG washout rate (WR). We divided patients into 2 groups: 27 responders whose EF increased by more than 5% and 15 nonresponders whose EF increased by 5% or less. EF of responders increased by 15 +/- 5% and that of nonresponders by 1 +/- 4%. Although MIBG image-derived indexes of nonresponders remained unchanged, the delayed H/M (1.91 +/- 0.34 v 2.24 +/- 0.53, P <.01) and WR (49 +/- 11 v 39 +/- 9%, P <.01) of responders improved, respectively. The plasma ANP (51 +/- 50 v 27 +/- 24 pg/mL, P <.01) and BNP (194 +/- 197 v 49 +/- 62 pg/mL, P <.01) levels of responders decreased. The degree of changes in the plasma BNP level correlated with changes in EF (r = -.698, P <.01). Conclusion: The improvement in EF with carvedilol therapy was proved to be accompanied by an improvement in neurohumoral factors.