[en] There is some controversy whether or not nitroglycerin improves blood flow to the ischemic myocardial zone. One aspect of the study was to determine the effect of nitroglycerin on thallium-201 distribution in patients with myocardial infarction. The results suggest that nitroglycerin may improve blood flow to an ischemic zone and that thallium-201 myocardial imaging (TMI) before. and after nitroglycerin may thus indicate viability of the myocardium. It needs further investigation to prove whether this myocardial tissue may profit from bypass graft surgery. Second aspect of the study was to find a pharmacological tool to detect viable myocardium inside or around TMI defects