Limits of Global Electrical Heterogeneity (GEH) Parameters in Patients with Normal Electrocardiograms and No Known Cardiovascular Disease Calculator

Hans F. Stabenau and Jonathan W. Waks
Harvard Throndike Arrhythmia Institute
Beth Israel Deaconess Medical Center
Boston, MA


Last update: 9/4/2023

About this calculator:

This calculator displays forecast values and 95% prediction intervals of GEH vectorcardiographic parameters, based on linear regression models constructed from vectorcardiographic projections of digital ECG measurements on N=3,292 patients who had normal ECGs and no known cardiac diagnoses (see Stabenau et al Limits of the Spatial Ventricular Gradient and QRST Angles in Patients with Normal Electrocardiograms and No Known Cardiovascular Disease Stratified by Age, Sex, and Race, Journal of Cardiovascular Electrophysiology, 2023.). QRST angles and associated percentiles in this population were instead modeled using quantile regression, as they are strongly non-normally distributed.

GEH measurements quantify changes in depolarization and repolarization which have been shown to be prognostically important in a variety of settings, including risk stratification for sudden cardiac death in the general population, appropriate primary prevention implantable cardioverter-defibrillator therapies, and other cardiovascular diseases. BRAVEHEART, the open-source software which was used to annotate the ECGs and measure GEH parameters is available at here.

This calculator and its results are for research purposes only and are not intended to diagnose or treat any disease.


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GEH Normal Limits Estimations:

            
Parameter    
Mean
   
95% CI
   
Units

   

   

   

SVG Magnitude    
   
[ - ]
    mV*ms
SVG Azimuth    
   
[ - ]
    Deg
SVG Elevation    
   
[ - ]
    Deg
SVG X    
   
[ - ]
    mV*ms
SVG Y    
   
[ - ]
    mV*ms
SVG Z    
   
[ - ]
    mV*ms
SAI VM    
   
[ - ]
    mV*ms


Parameter    
Median
   
P2.5 - P97.5
   
Units

   

   

   

Mean QRST Angle    
   
[ - ]
    Deg
Peak QRST Angle    
   
[ - ]
    Deg