Assessment of regional sympathetic nerve activity in vasospastic angina: Analysis of iodine 123-labeled metaiodobenzylguanidine scintigraphy

With the use of iodine 123-labeled metaiodobenzylguanidine (I-123-MIBG) scintigraphy, this study evaluated regional sympathetic nerve activity in vasospastic angina. Twenty male patients with left anterior descending coronary artery spasm and 18 male patients with normal coronary arteries as a control group were studied. All patients underwent quantitative I-123-MIBG scintigraphy and atropine stress I-123-MIBG scintigraphy. Both groups showed a similar heterogeneous I-123-MIBG uptake in the left ventricle. However, the regional washout rate in patients with coronary artery spasm was significantly reduced in all three territories compared with that in the control group. In vasospastic angina, the regional washout rate in the left anterior descending coronary artery territory was significantly reduced as compared with the other two regions. After intravenous injection of 1 mg atropine, the regional washout rate in the three regions significantly increased in both groups, but the regional differences between the two groups disappeared. The current study demonstrated that cardiac sympathetic nerve activity in vasospastic angina was suppressed, especially in the territory of the spasm-induced coronary artery, probably because of the enhanced parasympathetic nerve activity.