Hemodynamic Effects of Hyperbaric Oxygenation in Experimental Acute Myocardial Infarction

The hemodynamic effects of hyperbaric oxygenation were investigated in anesthetized dogs with acute myocardial embolism and infarction produced by injecting plastic spheres 325 micra in diameter. In 50 "control" animals with acute myocardial infarction induced while breathing either air at one atmosphere, 100% oxygen at one atmosphere or 7% oxygen at three atmospheres, 24-hour mortality was 85 to 90%. In 23 animals that received the same dose of microspheres and breathed 95 to 100% oxygen at three atmospheres for two hours following embolization, there was significantly less 24-hour mortality (30%), less ventricular fibrillation, and less advanced atrioventricular block. Hyperbaric oxygenation afforded protection against immediate mortality from ventricular fibrillation and also against later death, in shock, occurring within 24 hours of coronary embolization but after the immediate postembolization period had passed. In the animals exposed to hyperbaric oxygenation, declines of cardiac output and of cent...