Anti-beta 1-adrenoreceptor autoantibodies and myocardial sympathetic nerve activity in chronic heart failure

The autoantibodies stimulate the beta1-adrenoreceptors on cardiac myocytes similar to norepinephrine, and are associated with reduced cardiac function. Iodine-123 metaiodobenzylguanidine ((123)I-MIBG) is metabolized similarly to norepinephrine. This study was undertaken to investigate the relationship between cardiac stimulation by anti-beta1-adrenoreceptor autoantibodies and myocardial sympathetic nervous activity in patients with chronic heart failure.

We screened for the anti-beta1-adrenoreceptor autoantibodies in 52 patients with chronic heart failure by conducting an enzyme-linked immunosorbent assay, and underwent (123)I-MIBG scintigraphy in 27 of the patients. Anterior planar images of (123)I-MIBG were obtained 15 min and 3 h after the injection. We determined the heart to mediastinum radioactivity ratio (H/M), and calculated the rate of washout of (123)I-MIBG from the heart.

Patients with New York Heart Association functional class III or IV had higher levels of anti-beta1-adrenoreceptor autoantibodies than those with class I or II (p<0.01). The autoantibody level was significantly correlated with delayed H/M (r=-0.65, p<0.001) and washout rate (r=0.65, p<0.001). Sixteen patients with a cardiac event showed higher levels of the autoantibodies (p<0.05). Cardiac event-free survival was poorer in patients with the autoantibody levels >10 U/ml than that <10 U/ml (log-rank=12.1, p<0.001).

The anti-beta1-adrenoreceptor autoantibodies are closely associated with cardiac sympathetic nervous activity assessed by (123)I-MIBG and cardiac event in patients with chronic heart failure.