HALOTHANE IMPROVES THE BALANCE OF OXYGEN SUPPLY TO DEMAND IN ACUTE EXPERIMENTAL MYOCARDIAL ISCHAEMIA

Abstract

Acute myocardial infarction was induced by ligation of the anterior descending branch of the left main coronary artery in greyhound dogs anesthetized with pentobarbitone. Blood flow in the area of ischemia was measured by Xe clearance and compared with flow in the circumflex artery, measured with electromagnetic flow meters. Halothane, 1% produced an .apprx. 40% reduction in flow to both ischemic and normal areas in association with a 20% reduction in collateral perfusion pressure and a 40% reduction in mean arterial pressure. Comparison of the percentage change in the ratio of O2 availability: consumption in response to halothane revealed a significant difference between the ischemic and the normal areas. The former increased to 113 .+-. 9.3% (mean .+-. SEM [standard error of the mean]), while the latter decreased to 91 .+-. 5.02%. In the non-failing heart, halothane improves oxygenation in areas of acute myocardial ischemia.