T Wave Amplitude Deviation as a Participation Marker of Glycolysis in Myocardial Repolarization

Glucose metabolism is essential for heart physiology, especially in ischemic conditions. Anaerobic glycolysis participates along with aerobic fatty acid oxidation in generating energy supply, and the balance is shifted towards fatty acids. In the case of aerobic path restriction due to coronary artery disease (CAD), this ratio changes. The aim of the present research was to discover the aspects of glycolysis in cardiac electrophysiology. We utilized the normalized (by average value) T wave amplitude deviation values, named the G criterion, from high-resolution, 12-channel, 120-seconds-long electrocardiograms, which were obtained using DACG technology. The calculated G criterion allows a quantitative assessment of the ischemic process and corresponds to the functional class (FC) according to the Canadian cardiovascular classification. We examined 22 healthy people and 79 proven CAD patients: 24 II FC, 40 III FC and 15 IV FC by original ECG and fasting blood sugar tests. A strong correlation was found between the average G criterion from all 12 channels and the level of fasting blood sugar (r = +0.88). In the control group, blood sugar levels were 91 ± 6.5 mg/dl, II FC 103 ± 14.8 mg/dl (p < 0.01), III FC 113 ± 23.4 mg/dl (p < 0.001), and IV FC 152 ± 42.4 (p < 0.001). Moreover, the correlation factor (average G criterion and blood sugar) was strong and positive in each group: control +0.72, II FC +0.83, III FC +0.76, and IV FC +0.89. For the first time, heart electrical activity from the ECG curve was associated with high glucose level as one of the main CAD risk factors. The presence of such dependence of increased blood sugar level from the severity of the ischemic process in the myocardium indicates that hyperglycemic reaction is adaptive and can accelerate the anaerobic glycolysis for energy demand compensation in heart muscle.