Author:

Keywords:

Animals, Cerium Isotopes, Chromium Radioisotopes, Collateral Circulation, Coronary Circulation, Coronary Disease, Coronary Vessels, Disease Models, Animal, Dogs, Female, Iodine Radioisotopes, Male, Microspheres, Niobium, Radioisotopes, Strontium Radioisotopes, 1102 Cardiorespiratory Medicine and Haematology, Cardiovascular System & Hematology

Abstract:

Radioactive tracer microspheres (15 μ and 8-10 μ O.D.) were injected into the left atrium of 18 pure bred Beagles and in 18 mongrel dogs. The distribution of microspheres in the left ventricular myocardium was studied during normal coronary perfusion and during occlusion of the left anterior descending or left circumflex branch of the coronary artery. Under normal conditions the endocardial muscle layers received more blood than the epicardial muscle layers. This observation was more pronounced in Beagles as compared to mongrels. Ratios higher than unity were found irrespective of TM size but with 8-10 μ beads the endo/epi ratio was closer to one than with 15 μ TM. The collateral flow in acute LAD occlusion was 31.5% of normal resting LAD flow in pure bred Beagles. Collateral flow during LC-occlusion was 18.5% of normal resting flow in Beagles but only 8.6% in mongrels. These results were independent of TM size. The differences of collateral flow between perfusion areas were explained by differences in the amount of muscle to be supplied by a collateral network common to both areas. Collateral flow was non-homogeneously distributed: endocardial layers received less blood than epicardial layers. © 1974 Dr. Dietrich Steinkopff Verlag.