Importance of preoperative myocardial glycogen levels in human cardiac preservation. Preliminary report

Abstract

One hundred seventeen patients undergoing elective coronary bypass were divided into four groups according to prebypass myocardial glycogen levels and the use of potassium chloride cardioplegia. Myocardial glycogen levels were enhanced with a preoperative fat loading diet and overnight glucose loading. The control group (n = 27) which had mean cardiac glycogen levels of 750 mg/100 gm heart weight and no cardioplegia, had a transmural myocardial infarct rate of 14.4%; 35% had severe atrial arrhythmias 65% had severe ventricular arrhythmias, and 31% had severe vasopressor dependence. The group (n = 30) with low cardiac glycogen (736 mg/100 gm) and with potassium chloride cardioplegia had an infarct rate of 6.4%; 6.7% had severe atrial arrhythmias, 18% had severe ventricular arrhythmias, and 16.7% had severe vasopressor dependence. However, the group (n = 26) which had high cardiac glycogen levels (1,208 mg/100 gm) and no cardioplegia had no myocardial infarctions; 3.8% had severe atrial arrhythmias, 27% had severe ventricular arrhythmias, and only 7.8% had severe vasopressor need. The group (n = 34) which had high glycogen levels (1,516 mg/100 gm) and potassium chloride cardioplegia did best of all with no myocardial infarctions or no severe atrial arrhythmias; 14% had severe ventricular arrhythmias and 2.81% severe vasopressor need. The lessening of vasopressor dependence and severe atrial and ventricular arrhythmias were significant by chi square contingency tables at p less than 0.05 and p less than 0.001, respectively. One cardiac-related death each occurred in the two groups with low glycogen and none in those with high glycogen levels. This suggests that better preoperative cardiac nutrition as represented by enhanced cardiac glycogen helps that heart tolerate anoxic stress whether cardioplegia is utilized or not and is additive to potassium chloride cardioplegia.