EXPERIMENTAL CORONARY-ARTERY OCCLUSION .2. SPATIAL AND TEMPORAL EVOLUTION OF INFARCTS IN THE DOG HEART

The left anterior descending coronary artery was proximally ligated in 50 anesthetized dogs. These animals were subdivided into groups studied for infarct size following 45, 90, 120, 240 and 360 minutes of occlusion. Reflow was established after these occlusion times, the animals were allowed to recover and infarct size was determined either by conventional histology or by enzyme-macrohistochemistry. These animals were compared with a group of dogs studied 48 hrs after occlusion without reperfusion. We found that histologic and macrohistochemical infarct size determinations produced identical results. -About 75% of the area-at-risk undergo recrosis following permanent occlusion. Similar infarct sizes were obtained 4 and 6 hours after occlusion. After 90 minutes of occlusion 60% of the area-at-risk are irreversibly damaged. Necrosis begins in the central subendocardial zone, spreads first towards the borders of perfusion and extends toward the subepicardium. 90 minutes after occlusion subendocardial necrosis is complete. This implies that interventions aimed at reducing infarct size should aim at salvaging as much subepicardial muscle as possible. Infarct size as compared to the area-at-risk is larger in apical regions as compared to more basal regions. © 1979 Dr. Dietrich Steinkopff Verlag.