The Effects of Hyperlipidemia and Hypoglycemia on Myocardial Contractile Function and Oxygen Utilization During Coronary Hypoperfusion

Hart, Bradley Joe, The Effects of Hyperlipidemia and Hypoglycemia on Myocardial Contractile Function and Oxygen Utilization During Coronary Hypoperfusion Master of Science (Biomedical Sciences), August, 1998, 85 pp., 1 table, 5 figures, references, 51 titles. This study was designed to determine the effects of elevated fatty acid and lowered glucose concentrations on myocardial contractile function and substrate selection during hypoperfusion. Coronary perfusion pressure (CPP) was lowered in the left anterior descending coronary artery of open-chest anesthetized dogs. Glucose uptake, fatty acid uptake, and percent segment shortening (%SS) were determined with normal arterial FFA concentrations (Group 1) or with elevated concentrations (Groups 2 and 3). When glucose was removed by dialysis in Group 3, FFA uptake increased and glucose uptake decreased relative to Group 1 at 40 mmHg CPP (p [less than] 0.05). Oxygen consumption significantly increased (p [less than] 0.05); however, %SS was unchanged. Thus, although the myocardium switches from fatty acid to glucose metabolism to increase oxygen utilization efficiency during hypoperfusion, blocking this switch does not contribute to a further decrease in myocardial contractile function.