Summary: Experimental data show that myocardial infarction (MI) results in regional depletion of myocardial cathecholamines more extensively than necrosis. To investigate the extent ofadrenergic deneivation post MI in humans, we examined 16 palients. 59 k I2 yeas old, with recent (7-I2 days) MI. Resting thallium-201 (201TI) single photon emission computerized tomography (SPECT) imaging was performed to assess necrosis: tiietaiodobenzylguanidine 1123 (MIBG) SPECT was used to evaluate adrenergic denervation. ""TI and MIBG defects were evaluated quantitatively using polar maps, and differences in defects were expressed as percent of total polar map. In all paticnts, MIBG defect was larger than '"'TI defect, and difference ranged from 19 to 61 % (39.5 t-13.2%). Thrombolysis and age >60 did not influence the difference. Anterior MI showed larger differences (44 t-13 vs. 32 t-I I %, p < 0.05); patients with ischemic electrocardiographic (ECG) changes in leads without abnormal Q waves had larger differences (45 k 9 vs. 33 14%. p

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