Importance of Free Fatty Acids as a Determinant of Myocardial Oxygen Consumption and Myocardial Ischemic Injury during Norepinephrine Infusion in Dogs

Ole D. Mjøs; John K. Kjekshus; Jon Lekven

doi:10.1172/JCI107676

Importance of Free Fatty Acids as a Determinant of Myocardial Oxygen Consumption and Myocardial Ischemic Injury during Norepinephrine Infusion in Dogs

Ole D. Mjøs, John K. Kjekshus, and Jon Lekven

Published May 1, 1974 - More info

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Abstract

Increased delivery of free fatty acids raises myocardial oxygen consumption (ṀVO₂) without influencing mechanical performance. The effects of norepinephrine on ṀVO₂ and on the size of ischemic injury after acute coronary occlusion were therefore studied before and during inhibition of lipolysis with β-pyridylcarbinol. In spite of similar mechanical responses to norepinephrine, ṀVO₂ increased by 57±11% before and significantly less, 31±6%, (P < 0.01) during inhibition of lipolysis. After coronary occlusion the ischemic injury associated with norepinephrine infusion, as evidenced by epicardial mapping of S-T segment elevation, was larger before (7.9±1.1 mV) than during inhibited lipolysis (2.8±0.4 mV; P < 0.005). Average S-T segment elevation associated with norepinephrine infusion during inhibited lipolysis (2.8±0.4 mV) was even lower (P < 0.05) than during control occlusion alone, before drug administration (4.4±0.7 mV). In conjunction with an antilipolytic agent, norepinephrine was shown to reduce the extent and magnitude of the myocardial ischemic injury produced by acute coronary occlusion; this could be due to an improved balance between myocardial oxygen supply and requirement.

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