Iodine-123-metaiodobenzylguanidine (123I-MIBG) has been used to assess the integrity and function of the cardiac sympathetic nervous system in patients with heart failure. Heart-type fatty acid binding protein (H-FABP) is released into the circulation when the myocardium is injured, and H-FABP has been recently used as a novel marker for the diagnosis of ongoing myocardial damage.
Objective: The aim of the present study was to compare cardiac sympathetic nervous activity assessed by 123I-MIBG imaging with serum levels of H-FABP in patients with heart failure.
Methods: Fifty patients with chronic heart failure were studied. 123I-MIBG imaging was carried out at 30 min (early) and 240 min (delayed) after the tracer injection. We measured serum levels of H-FABP using a sandwich enzyme linked immunosorbent assay.
Results: Heart to mediastinum (H/M) ratios of 123I-MIBG decreased and washout rate increased with higher New York Heart Association (NYHA) functional class. H-FABP, norepinephrine and brain natriuretic peptide (BNP) levels increased as the severity of NYHA class advanced. Delayed H/M ratio was significantly correlated with H-FABP (r = -0.296, p = 0.029) and BNP (r = -0.335, p = 0.0213). Myocardial washout rate of 123I-MIBG was also correlated with H-FABP (r = 0.469, p < 0.001), norepinephrine (r = 0.433, p = 0.005), and BNP (r = 0.465, p = 0.001).
Conclusions: These data suggest that cardiac sympathetic nervous activation was associated with ongoing cardiomyocyte damage characterized by an elevated serum level of H-FABP in patients with heart failure. 123I-MIBG imaging is an appropriate approach to evaluate non-invasively not only cardiac sympathetic nervous activity, but also latent ongoing myocardial damage in the failing heart.