Importance of the heart vector origin point definition for an ECG analysis: The Atherosclerosis Risk in Communities (ARIC) study

Abstract

Aim —Our goal was to investigate the effect of a global XYZ median beat construction and the heart vector origin point definition on predictive accuracy of ECG biomarkers of sudden cardiac death (SCD). Methods —Atherosclerosis Risk In Community study participants with analyzable digital ECGs were included (n=15,768; 55% female, 73% white, mean age 54.2±5.8 y). We developed an algorithm to automatically detect the heart vector origin point on a median beat. Three different approaches to construct a global XYZ beat and two methods to locate origin point were compared. Global electrical heterogeneity was measured by sum absolute QRST integral (SAI QRST), spatial QRS-T angle, and spatial ventricular gradient (SVG) magnitude, azimuth, and elevation. Adjudicated SCD served as the primary outcome. Results —There was high intra-observer (kappa 0.972) and inter-observer (kappa 0.984) agreement in a heart vector origin definition between an automated algorithm and a human. QRS was wider in a median beat that was constructed using R-peak alignment than in time-coherent beat (88.1±16.7 vs. 83.7±15.9 ms; P<0.0001), and on a median beat constructed using QRS-onset as a zeroed baseline, vs. isoelectric origin point (86.7±15.9 vs. 83.7±15.9 ms; P<0.0001). ROC AUC was significantly larger for QRS, QT, peak QRS-T angle, SVG elevation, and SAI QRST if measured on a time-coherent median beat, and for SAI QRST and SVG magnitude if measured on a median beat using isoelectric origin point. Conclusion —Time-coherent global XYZ median beat with physiologically meaningful definition of the heart vector’s origin point improved predictive accuracy of SCD biomarkers.

Does Sex Modify an Association of Electrophysiological Substrate with Sudden Cardiac Death? The Atherosclerosis Risk in Communities (ARIC) Study

“…To measure peak-vector-based GEH metrics, we constructed time-coherent median beat and defined isoelectric heart vector origin point, as described. 17 The MATLAB (MathWorks, Natick, MA, USA) software code for the heart vector origin definition is provided at https://github.com/Tereshchenkolab/Origin. In this study we included only participants with a normal sinus median beat.…”

Dynamic Predictive Accuracy of Electrocardiographic Biomarkers of Sudden Cardiac Death within a Survival Framework: The Atherosclerosis Risk in Communities (ARIC) study

“…GEH was measured as previously described, 3,12 in a time-coherent median meat with identified origin of the heart vector. 13 We have provided the software code at Physionet (https://physionet.org/physiotools/geh/). In addition to previously reported "mean" GEH measures, 3 in this study we measured the spatial peak vectors ( Figure 3…”

“…15 Next, we constructed time-coherent median beat, and detected origin of the heart vector, using our novel approach, as recently described. 13 Then, we performed calculations of GEH metrics, using the following equations.…”

Mining hidden information in the P waves

“…As we approach the centennial of Einthoven's Nobel prize, the ECG continues to engender basic and clinical investigations. Furthermore, there has been a renewed interest in vectorcardiographic indices, powered in part by the ability to better acquire and manipulate digital data …”

“…Furthermore, there has been a renewed interest in vectorcardiographic indices, powered in part by the ability to better acquire and manipulate digital data. 3 Given that sudden cardiac death (SCD) accounts for approximately 50% of all-cause cardiovascular mortality, 4 there is understandably a growing enthusiasm for identifying novel ECG markers that can aid in risk-stratification for experiencing a potentially lethal ventricular tachyarrhythmia. There are numerous conditions that herald a high risk for SCD, many which are often recognized on the surface ECG.…”