Myocardial metabolism during perfusion of the coronary circulation with gaseous oxygen

The isolated dog heart continues to beat for prolonged periods when the coronary circulation is perfused solely with gaseous oxygen. Determinations of myocardial glycogen and lactate levels indicate that oxygen is metabolically utilized under these circumstances. In control preparations without oxygen perfusion, the glycogen is rapidly depleted with a marked increase in myocardial lactate. With oxygen perfusion, glycogen levels remained appreciable for prolonged periods and the lactate concentration persisted at essentially normal levels. These data indicate that oxygen is utilized by the myocardium in carbohydrate metabolism when perfused through the coronary circulation in the gaseous state.