Myocardial energy metabolism in the induction phase of cardioplegia in relation to myocardial temperature during open heart surgery. 
Changes in myocardial high energy phosphate and lactate concentrations during initiation of cardioplegia for open heart surgery were studied in 21 patients and related to their individual myocardial temperatures.  Left ventricular myocardial biopsies were taken 10 min post aortic cross-clamping and were analysed for ATP, creatine phosphate (CP), creatine (C) and lactate.  The patients were divided into three groups according to the achieved myocardial temperature: 6-10 degrees C, 11-15 degrees C and 16-24 degrees C. The results indicated that optimal myocardial protection during the induction phase of the cardioplegia was obtained in the 11-15 degrees C group in which the highest ATP concentration and simultaneously lowest lactate concentration was maintained.