A COMPARISON OF THE EFFECT OF HEMORRHAGE AND INFUSED CATECHOLAMINES ON VENTRICULAR PERFORMANCE, CORONARY FLOW AND MYOCARDIAL OXYGEN CONSUMPTION

¹ Department of Pediatrics, Harvard Medical School; Cardiology Division of the Medical Service, Children's Hospital, Medical Center, Boston, Massachusetts

In an isolated dog heart which was perfused through the coronary arteries with arterial blood from an anesthetized donor dog, left ventricular performance, coronary flow and myocardial oxygen consumption were observed during control periods, during periods in which the donor was made hypotensive by phlebotomy and during periods in which epinephrine and norepinephrine were infused into the coronary circulation of the isolated heart. When the donor was made hypotensive by phlebotomy, blood levels of epinephrine and norepinephrine increased, as did the left ventricular performance, the coronary flow and the myocardial oxygen consumption of the isolated heart. When epinephrine and norepinephrine were infused into the coronary circulation of the isolated heart in sufficient quantities to produce an increase in left ventricular performance comparable to that accompanying hemorrhage in the donor, the combined epinephrine and norepinephrine level as well as the coronary flow were found to be relatively increased while the myocardial oxygen consumption remained unchanged. These findings imply that the positive inotropic effect that accompanies the in vivo release of epinephrine and norepinephrine during hemorrhage cannot be achieved by the simple attainment of comparable levels of epinephrine and norepinephrine alone.