A review of beat-to-beat vectorcardiographic (VCG) parameters for analyzing repolarization variability in ECG signals

Abstract

Elevated ventricular repolarization lability is believed to be linked to the risk of ventricular tachycardia/ventricular fibrillation. However, ventricular repolarization is a complex electrical phenomenon, and abnormalities in ventricular repolarization are not completely understood. To evaluate repolarization lability, vectorcardiography (VCG) is an alternative approach where the electrocardiographic (ECG) signal can be considered as possessing both magnitude and direction. Recent research has shown that VCG is advantageous over ECG signal analysis for identification of repolarization abnormality. One of the key reasons is that the VCG approach does not rely on exact identification of the T-wave offset, which improves the reproducibility of the VCG technique. However, beat-to-beat variability in VCG is an emerging area for the investigation of repolarization abnormality though not yet fully realized. Therefore, the purpose of this review is to explore the techniques, findings, and efficacy of beat-to-beat VCG parameters for analyzing repolarization lability, which may have potential utility for further study.

Temporal variability of T‐wave morphology and risk of sudden cardiac death in patients with coronary artery disease

“…During recent decades, three-dimensional vectorcardiography (VCG) has attracted attention as a potential method to gain new prognostic parameters for cardiovascular risk assessment (Hasan & Abbott, 2016). Spatiotemporal changes in the electrophysiology of myocardium can be measured using VCG-derived parameters that yield information beyond that of the conventional electrocardiogram (ECG) (Verrier & Huikuri, 2017).…”

“…These evaluation methods, however, still fail to outline the largest subgroup of CAD patients that are at high risk for SCD: the ones that do not have ventricular dysfunction or any other manifestation of CAD prior to their sudden death (Deyell et al., 2015). During recent decades, three‐dimensional vectorcardiography (VCG) has attracted attention as a potential method to gain new prognostic parameters for cardiovascular risk assessment (Hasan & Abbott, 2016). Spatiotemporal changes in the electrophysiology of myocardium can be measured using VCG‐derived parameters that yield information beyond that of the conventional electrocardiogram (ECG) (Verrier & Huikuri, 2017).…”

“…Spatiotemporal changes in the electrophysiology of myocardium can be measured using VCG‐derived parameters that yield information beyond that of the conventional electrocardiogram (ECG) (Verrier & Huikuri, 2017). Although the ECG has brought well established and widely available indices, such as the QT interval, that characterize electrocardiographic repolarization, the methodology has been limited by the fact that it is one‐dimensional (i.e., consisting of only the magnitude of heart signal) and does not reveal three‐dimensional features of electrocardiographic repolarization (Hasan & Abbott, 2016). The VCG, on the other hand, goes further and measures both direction and magnitude of cardiac electrical activity in spatial planes, thus allowing a much more complete outlook on cardiac repolarization dynamics (Yang et al., 2012).…”

“…The VCG, on the other hand, goes further and measures both direction and magnitude of cardiac electrical activity in spatial planes, thus allowing a much more complete outlook on cardiac repolarization dynamics (Yang et al., 2012). Current VCG methodology is not without its own limitations, which include the need to further validate existing parameters, lack of VCG measurement options routinely available in contemporary electrocardiographic analysis software, and the fact that most clinicians still are not familiar with the technology (Hasan & Abbott, 2016). A study of temporal variability in repolarization heterogeneity by using VCG parameters is an emerging area of investigation, though its full potential is yet to be explored (Hasan & Abbott, 2016).…”

Biosignal processing

“…Hasan and Abott [3] review recent developments in the field of vectorcardiography (VCG), which uses the spatial information usually not considered in multi-lead ECG analysis.…”