Preservation of high energy phosphates during ischaemic cardiac arrest with glucose

The possible myocardial protection by glucose-insulin-potassium infusion prior to cardioplegic ischaemic arrest was studied in rats. One group of animals was given intravenous infusions of high concentrations of glucose during 3 days. A control group received the same amount of saline. The isolated hearts were subjected to Langendorff perfusion followed by cardioplegic arrest at 15 degrees C for a period of 2 or 3.5 hours. The hearts were then subjected to reperfusion for a period of 45 min for those sustaining 2 hours of ischaemia and 60 min for those sustaining 3.5 hours of ischaemia. In the hearts that suffered 2 hours of ischaemia there were no differences in myocardial content of high energy phosphate compounds between the pretreated and controls, and there was no evidence of creatine kinase release. In the hearts exposed to 3.5 hours ischaemia, myocardial content of high energy phosphates was significantly higher in the pretreated than in the controls. The release of creatine kinase was also less, but this difference was not significant. The study indicates that preoperative treatment with glucose-insulin-potassium may improve myocardial tolerance to ischaemia.