Scintigraphic detection of regional disruption of the adrenergic nervous system in sarcoid heart disease

Abstract

The presence of defects on resting thallium (201TI) myocardial scintigraphy has been previously demonstrated in myocardial sarcoidosis. To examine cardiac sympathetic nerve activity in patients with cardiac sarcoidosis, we performed 201TI and I-123 MIBG (meta-iodobenzylguanidine) myocardial scintigraphy in patients with sarcoidosis. Sixteen patients with sarcoidosis were classified into 2 groups according to the presence or absence of defects on 201TI scintigraphy. Myocardial images by both 201TI and I-123 MIBG were then divided into 20 segments and scored using a 6-point scoring system. Defect Score was defined as a the sum of significant scores in each image. The mean Defect Score in I-123 MIBG images was higher in the 201TI defect group (44.3 ± 13.3) than in both the normal 201TI group (25.1 ± 10.5) and the control group (22.7 ± 11.4). Moreover, the locations of defects on I-123 MIBG scans were consistent with those on 201TI scans. This study suggest that cardiac adrenergic function may be impaired in cardiac sarcoidosis, and I-123 MIBG scintigraphy may be more sensitive in detecting cardiac sarcoidosis than 201TI scintigraphy, although the clinical significance of these findings requires further study.