title: The effect of some pathophysiological factors on radioisotope evaluation of regional myocardial ischaemia.
abstract: Scintigraphic demonstration of regional myocardial ischaemia is modified by some pathophysiological factors. Among 146 patients the percentage of angiographically visualized collaterals increased with the severity of coronary damage. The authors presume that collaterals diminish the hypoperfusion. Reactive hyperaemia was demonstrated in the surrounding nonischaemic myocardium of dogs and in the area of a short ischaemia during reperfusion. These changes may overlay the ischaemic area and alter its demonstration. The higher uptake of 42K in the ventricular myocardium of rabbits as compared with 86Rb uptake indicates a different affinity of potassium analogues to the myocardium. The authors demonstrated in experiments on rats with regional myocardial ischaemia that 86Rb is quickly washed out from the nonischaemic myocardium within 30 minutes after its intravenous injection. The greatest 86Rb concentration difference between ischaemic and intact myocardium was seen in animals with 10-minute ischaemia, and was smaller in ischaemia lasting for 30 and 60 minutes.
mesh_terms: D000818:Animals; D003326:Coronary Circulation; D003327:Coronary Disease / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging; D004285:Dogs; D006439:Hemodynamics; D006801:Humans; D009206:Myocardium / Q000378:metabolism; D011197:Potassium Radioisotopes / Q000378:metabolism; D011868:Radioisotopes / Q000378:metabolism; D011877:Radionuclide Imaging; D012413:Rubidium / Q000378:metabolism
chemical_list: D011197:Potassium Radioisotopes; D011868:Radioisotopes; D012413:Rubidium