ABNORMAL CARDIAC SYMPATHETIC-NERVE FUNCTION IN A PATIENT WITH PHEOCHROMOCYTOMA - AN ANALYSIS USING I-123 METAIODOBENZYLGUANIDINE SCINTIGRAPHY

A 23-year-old woman with pheochromocytoma had a high level of plasma n orepinephrine (NE) (6039 pg/ml) and I-123 metaiodobenzylguanidine (MIB G) scintigram showed decreased myocardial retention. After surgical re section, plasma norepinephirine was normalized and the myocardial rete ntion of I-123 MIBG gradually improved. These findings suggest that th e possibility that the excess of circulating norepinephirine caused by pheochromocytoma could damage the cardiac sympathetic nerve function and I-123 MIBG scintigraphy is a useful method of evaluating abnormali ties.