Electrocardiographic Changes in Certain Cardiovascular Physiological and Pathological Settings. Impact on Coronary Artery Bypass Grafting

Abstract

Review on electrocardiographic changes provoked by aging, diagnostic tests, cardiac surgery, hemodialysis, diabetes, etc., is the objective of the current material. Several electrocardiographic (ECG) parameters that are well known risk markers of arrhythmias, incidental heart failure and sudden cardiac death (SCD) are discussed: QRS amplitude, QRS morphology, QRS duration, QRS alternans, T-wave amplitude, T-wave morphology, T-wave alternans, negative T-waves, 3D-spatial angle between maximal QRS and T vectors of the vectorcardiographic loops, ST-segment elevation, QT-interval dispersion, and heart rate. All reviewed parameters are compared with the results on the ECG-alterations, induced by coronary artery bypass grafting (CABG) surgery. Two parameters showed an improvement in the patients' condition: QRS-T angle and cardiac autonomic innervation while two others (T-wave alternans and heart rate) indicated deterioration. We tend to assume that the deterioration in this early post-operative period is an effect of the post-surgery trauma. We speculate that this effect will fade away in a period of a month and more after surgery, and we intend to conduct such a research in the future. The analysis of ECG's changes will help to better assess the impact of the CABG surgery.

Keywords

• Coronary artery bypass grafting
• Electrocardiography
• T-wave alternans
• ST-elevation
• Hearth failure
• Cardiac death