Temporary coronary occlusion in conscious dogs: collateral flow and electrocardiogram

Abstract

The left circumflex coronary artery (LC) was catheterized and myocardial blood flow measured by the Kr85 method. LC occlusion was produced in unanesthetized dogs by a silastic balloon. Control flow was 71[plus or minus]20 (SD) ml/100 g per min. Collateral flow through the bed normally supplied by the occluded LC was 31[plus or minus]6 ml/100 g per min. Postocclusion hyperemia was 243[plus or minus]54 ml/100 g per min. and was followed by return to control flow (64[plus or minus]26). In acute experiments LC collateral flow decreased from 29[plus or minus]4 to 5[plus or minus]5 when LC and LAD coronary arteries were occluded. The pattern of collateral flow during LC occlusion was recorded by rapid sequence photography. Precordial ecg revealed progressive diminution of T-wave amplitude and ST segment depression. The unanesthetized dogs did not experience pain during LC occlusion.