Ischemia and reperfusion reduced cardiac work compared to aerobic control isolated working hearts. (A) Experimental protocol of hearts subjected to I/R. Arrow indicates when the mitochondrial isolation began. (B) Mechanical function of the heart after I/R injury. (C) Rates of glucose oxidation in isolated working rat hearts subjected to aerobic perfusion or I/R. (D) Rates of palmitate oxidation in isolated working rat hearts subjected to aerobic perfusion or I/R. Values represent the mean ± SEM of 9 hearts per group for mechanical function and 6 hearts per group for metabolic rates.* represents P < 0.05, significantly different from aerobic value.