Increased plasma levels of adrenomedullin in patients with hypertrophic cardiomyopathy: its relation to endothelin-I, natriuretic peptides and noradrenaline.

1. The aim of this study was to elucidate the pathophysiological role of adrenomedullin and the relation between adrenomedullin and other hormones in patients with hypertrophic cardiomyopathy. 2. Fourteen patients with hypertrophic obstructive cardiomyopathy (HOCM), 26 patients with hypertrophic non-obstructive cardiomyopathy (HNCM) and 14 normal control subjects participated in this study. Radioimmunoassay for plasma adrenomedullin concentration was performed with adrenomedullin-M antibody. Plasma levels of endothelin-1, atrial and brain natriuretic peptides and noradrenaline were also measured. 3. Plasma levels of adrenomedullin were higher in patients with hypertrophic cardiomyopathy (8.43 +/- 3.73 pmol/l) than in normal controls (5.24 +/- 0.44 pmol/l, P < 0.005). There was no significant difference between HOCM and HNCM patients. There was a weak correlation between plasma levels of adrenomedullin and total 12-lead QRS voltage in patients with hypertrophic cardiomyopathy (r = 0.323, P < 0.05). 4. Plasma levels of endothelin-1, atrial and brain natriuretic peptides were higher in hypertrophic cardiomyopathy than in normal controls. Endothelin-1 showed no significant difference between HOCM and HNCM patients, but atrial and brain natriuretic peptides were higher in HOCM than in HNCM patients. There was a positive correlation between plasma levels of adrenomedullin and endothelin-1 (r = 0.575, P < 0.0001), but no correlation between plasma levels of adrenomedullin and atrial natriuretic peptide, brain natriuretic peptide and noradrenaline. 5. Our results indicate that adrenomedullin may play an important role to maintain haemodynamics in patients with hypertrophic cardiomyopathy, and its action may be related to endothelin-1 but independent of atrial natriuretic peptide, brain natriuretic peptide and noradrenaline.