Glucose substrate in myocardial protection.

Glucose-insulin-potassium (GIK) was infused preoperatively in 30 patients scheduled for coronary artery operation. Before cardiopulmonary bypass (CPB) each patient received an intravenous infusion of 50% glucose. Myocardial protection was achieved with a cardioplegic solution containing glucose. A similar group of 30 patients received an equal volume of NaCl infused preoperatively and before CPB, and their cardioplegic solution contained no glucose. Clinically and by hemodynamic evaluation postoperatively one could not separate the two groups. Glycogen grading of the myocardium prior to bypass demonstrated no difference in glycogen levels in patients receiving glucose and those receiving NaCl. However, at the end of cardioplegic arrest only the group receiving glucose maintained normal grading of myocardial glycogen.