Abnormalities of myocardial sympathetic nerve function were reported in congestive heart failure (CHF). To assess myocardial sympathetic nerve function, we obtained metaiodobenzylguanidine (MIBG) images 15 min and 180 min after the injection of iodine-123 MIBG at a dose of 111 MBq and calculated the ratio of heart to mediastinum count (H/M) and the washout rates (WRs) in 59 consecutive patients with CHF and age-matched subjects without CHF (n=23). The plasma levels of B-type natriuretic peptide were measured. H/M ratio was significantly lower in the CHF group (1.8+/-0.9) than in the control group (2.6+/-0.4; P<0.01). WR was higher in the CHF group (38+/-4%) than in the control group (28+/-3%; P<0.01). H/M was inversely correlated with the plasma B-type natriuretic peptide (r=-0.46, P<0.05). Eighteen patients suffered cardiac events (two deaths, 16 hospitalizations) during a mean follow-up period of three years. Kaplan-Meier analysis showed that a low H/M was associated with a poor prognosis in patients with CHF. These findings indicate that the H/M ratio on MIBG imaging is a useful predictor of mortality and morbidity in patients with CHF.
Keywords: B-type natriuretic peptide; Congestive heart failure; Heart-to-mediastinum count ratio; Metaiodobenzylguanidine; Washout rates.