title: Relationship between total mechanical energy and oxygen consumption in the stunned myocardium.
abstract: We studied the relationship between left ventricular oxygen consumption (LVVO2) and total ventricular mechanical energy production as determined by calculation of the systolic pressure-volume area (P-VA) before and after 25 minutes of warm ischemia in 7 sheep. We compared the relationship between LVVO2 and P-VA with the relationships between LVVO2 and stroke work and between LVVO2 and the systolic stress integral. Using the methods presented, P-VA can be measured in vivo (n = 123) in both preischemic and postischemic hearts. Ischemia increases the slopes of the relationship between LVVO2 and P-VA and between stroke work and the systolic stress integral, and reduces the oxygen utilization efficiency of stroke work to less than 2%. Coefficients of determination for the relationship between LVVO2 and P-VA are, in general, higher than those between LVVO2 and either stroke work or the systolic stress integral. We conclude that systolic P-VA can be measured in vivo using recently developed methods and that it is applicable to postischemic "stunned" hearts. Because P-VA and LVVO2 can be converted into identical energy units, calculation of P-VA permits calculation of myocardial oxygen utilization efficiency.
authors.affiliation: Department of Surgery, School of Medicine, University of Pennsylvania, Philadelphia.
authors.forename: S
authors.initials: S
authors.lastname: Furukawa
authors.forename: J E
authors.initials: JE
authors.lastname: Bavaria
authors.forename: G
authors.initials: G
authors.lastname: Kreiner
authors.forename: L H
authors.initials: LH
authors.lastname: Edmunds
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D003326:Coronary Circulation; D003327:Coronary Disease / Q000378:metabolism / Q000503:physiopathology*; D004548:Elasticity; D004734:Energy Metabolism; D006321:Heart / Q000503:physiopathology*; D009200:Myocardial Contraction / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D012756:Sheep; D013318:Stroke Volume / Q000502:physiology