EVALUATION OF THE SYMPATHETIC NERVOUS-SYS TEM IN SILENT ISCHEMIA WITHI-123 METAIODOBENZYLGUANIDINE (MIBG)

Aim: Examination of the integrity of the sympathetic nervous system in patients with angiographically proven coronary artery disease and ECG documented asymptomatic ST-segment depression. Method: Stress and res t myocardial perfusion scintigraphy using either Thallium-201 or Tc-99 m-isonitrile was performed in SPECT technique in order to localize isc hemia or scar associated perfusion defects. 15 min and 4 h p.i. static anterior I-123-MIBG uptake was acquired. In order to localize norepin ephrine depletion 4 h p.i. additional I-123-MIBG SPECT acquisition was performed. Incidence of arrhythmias was investigated by Holter EGG. P atients with diabetes mellitus were excluded. Results: SPECT images sh owed in all patients regional I-123-MIBG depletion which corresponded with scintigraphically infarcted or ischemic regions. Well perfused my ocardial regions matched with regular I-123-MIBG uptake. There was no evidence of increased arrhythmias in long-term EGG. Conclusion: The fi nding of regular I-123-MIBG uptake in well-perfused myocardium and inf arction- or ischemia-associated regional I-123-MIBG depletion confirms that silent ischemia is not caused by a global sympathetic nervous dy sfunction in a sense of cardiac polyneuropathy.