[Characteristics of regional sympathetic innervation in diabetic patients with silent myocardial ischemia assessed by 123I-metaiodobenzylguanidine imaging].

The purpose of this study was to clarify any association between clinically detectable silent myocardial ischemia (SMI) and myocardial 123I-metaiodobenzyl-guanidine (MIBG) uptake. Subjects of this study were (1) patients with SMI with diabetes (n = 15), (2) patients with angina pectoris with diabetes (n = 15), (3) patients with SMI without diabetes (n = 8) and (4) normal subjects (n = 23). Subjects underwent planar and single photon-emission-computed tomography (SPECT) imaging 15 min and 3 hours after injection of 123I-MIBG. H/M ratio was significantly lower in diabetic SMI (2.1 +/- 0.3) and non-diabetic SMI (2.3 +/- 0.3) than control subjects (2.6 +/- 0.3). The inferior-to-anterior wall count ratio (I/A) in diabetic SMI group was the lowest among all groups (p < 0.05). A significant difference was observed in relative regional uptake in the inferior segment of the distal left ventricle between SMI and angina group in patients with diabetes mellitus (p < 0.05). The decreased MIBG uptake in the inferior wall may be an important sign of cardiac sympathetic dysfunction, suggesting the abnormalities in cardiac nervous system play an important role in the mechanism of diabetic silent myocardial ischemia.