Multiparametric Molecular Imaging Provides Mechanistic Insights into Sympathetic Innervation Impairment in the Viable Infarct Border Zone

Impaired catecholamine handling in the viable infarct border zone may play an important role in ventricular remodeling and lethal arrhythmia. We sought to get further biologic insights into cardiac sympathetic neuronal pathology after myocardial infarction, using multiple tomographic imaging techniques. Methods: In a porcine model of myocardial infarction (n 5 13), PET and MR imaging were performed after 4–6 wk and integrated with electrophysiologic test-ing and postmortem histology. Results: PET with the physiologic neurotransmitter 11C-epinephrine, which is sensitive to metabolic degradation unless it is stored and protected in neuronal vesicles, identified a defect exceeding the perfusion defect (defined by 13N-ammonia; defect size in all animals, 42 ± 12 vs. 35 % ± 12 % of left ventricle, P, 0.001). In a subgroup of 7 animals, defect of the metabolically resistant catecholamine 11C-hydroxyephedrine was smaller than epinephrine (41 ± 8 vs. 47 % ± 6 % of left ventricle, P