Evaluation of Sympathetic Nerve Function in Patients with Heart Failure by MIBG Myocardial Scintigraphy

Abstract

Patients with heart failure show signs of sympathetic dysfunction, including an elevation in blood norepinephrine levels, and down-regulation of beta-receptors. The reported changes in these patients include a reduction in the number of sympathetic nerves, and a decrease in myocardial norepinephrine (NE) content (1). ¹²³I-Metaiodobenzylguanidine (MIBG) has been developed for imaging of the kinetics of NE in vivo. MIBG uptake is reduced, and washout is increased in the failing heart due to increased turnover or spillover of NE plasma, poor retention, and NE re-uptake disorder at sympathetic nerve endings (2, 3). We performed this study to determine which parameter of ¹²³I-MIBG image is an accurate predictor of the response to beta-blocker therapy, and to evaluate differences in therapeutic effects among various beta-blockers in patients with dilated cardiomyopathy (DCM).