Myocardial responses to acute global ischemia and reperfusion

Effects of 15 to 120 minutes of global myocardial ischemia without coronary occlusion followed by 60 minutes of reperfusion were examined in anesthetized dogs on total coronary bypass. Thirty minutes or less of global ischemia was found to be fully recoverable, while longer periods of ischemia were associated with irreversible damage. Total and regional myocardial flows and myocardial oxygen consumption did not recover in animals subjected to 60 minutes of global ischemia, while hemodynamic dysfunction became apparent only after 90 minutes of global ischemia. These results indicate that global myocardial ischemia, like coronary artery ligation, will produce functional impairment during reperfusion which is dependent on the duration of the insult.