The effects of coronary artery ligation on transmural high-energy phosphates following 20 minutes of blood reflow.

Normal or elevated levels of ATP and phosphocreatine (PCr) were observed from the subepicardium to the subendocardium of the canine left ventricle after five and 20 minutes of left circumflex artery occlusion followed by 20 minutes of blood reflow. However, after two or four hours of occlusion, followed by reflow, ATP and PCr levels were markedly depressed, and a significant decreasing decreasing subepicardial to subendocardial gradient appeared, suggestive of inhibition of oxidative metabolism during extended periods of ischemia but not during short periods of ischemia.