Uptake of 99mTc heparin in isoproterenol damaged rat heart

99m Tc-Heparin (Tc-H) has been reported to concentrate in acute experimental myocardial infarct. In order to investigate the cardiac time course uptake of Tc-H after myocardial lesion initiation and to evaluate the early localization, the isoproterenol-induced myocardial necrosis model in rat was chosen. Results were expressed as % i.d./g and as damaged-to-normal heart ratio (DH/NH) comparing the whole heart activity in the treated animals to that of control rats. Concentration of Tc-H is significant greater in damaged myocardium than in that of control animals, also when isoproterenol and radiopharmaceutical were administered simultaneously. Uptake expressed either on a % i.d./g. basis or as DH/NH ratio is increasing from 0 to 3 hr p.i., afterwards it remains almost constant up to 12 hr, while the 24th hour value is very similar to that observed at 1 hour. The results are consistent with the hypothesis that Tc-H has a sufficient high affinity for damaged myocardium to allow scintigraphic detection