On the basis of the results which we obtained having performed 25 examinations on 15 patients with angina pectoris syndrome, myocardial infarctions and condition after bypass operation the preparation 123I hepatadecanoic acid produced in the Central Institute for Nuclear Research Rossendorf is very well suited for the scintigraphic demonstration of the myocardium. Moreover it is possible to recognize selectively diagnostically interesting regions with different radioactivity intake, retention and elimination of the radiopharmacon pharmacon and with the help of quantitative parameters to characterize concerning the metabolic efficiency. We consider the 123I hepatadecanoic acid suitable for the clinical use in establishing the global and regional metabolic efficiency of the myocardium. It is very well to be used for the primary diagnostics and represents an evident diagnostic remedy for the assessment of the course of myocardial diseases and the success of therapy.