The Spatial Ventricular Gradient is Associated with Inducibility of Ventricular Arrhythmias During Electrophysiology Study

Nicolas Isaza; Hans F Stabenau; Daniel B Kramer; Arunashis Sau; Patricia Tung; Timothy R Maher; Andrew Locke; Peter Zimetbaum; Andre d'Avila; Nicholas S Peters; Larisa G Tereshchenko; Fu Siong Ng; Alfred E Buxton; Jonathan W Waks

doi:10.1016/j.hrthm.2024.05.005

The Spatial Ventricular Gradient is Associated with Inducibility of Ventricular Arrhythmias During Electrophysiology Study

Heart Rhythm. 2024 May 6:S1547-5271(24)02542-6. doi: 10.1016/j.hrthm.2024.05.005. Online ahead of print.

Affiliations

¹ Harvard-Thorndike Arrhythmia Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
² Harvard-Thorndike Arrhythmia Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA; Smith Center for Outcomes Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
³ National Heart and Lung Institute, Imperial College London, UK; Department of Cardiology, Imperial College Healthcare NHS Trust, London, UK.
⁴ Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH; Heart, Vascular & Thoracic Institute, Cleveland Clinic, Cleveland, OH.
⁵ Harvard-Thorndike Arrhythmia Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA. Electronic address: jwaks@bidmc.harvard.edu.

PMID: 38718942
DOI: 10.1016/j.hrthm.2024.05.005

Abstract

Background: Myocardial electrical heterogeneity is critical for normal cardiac electromechanical function, but abnormal/excessive electrical heterogeneity is proarrhythmic. The spatial ventricular gradient (SVG), a vectorcardiographic measure of electrical heterogeneity, has been associated with arrhythmic events over long-term follow-up, but its relationship with short-term inducibility of ventricular arrhythmias (VAs) is unclear.

Objective: Determine associations between SVG and inducible VAs during electrophysiology study (EPS).

Methods: Retrospective study of adults without prior sustained VA, cardiac arrest, or implantable cardioverter-defibrillator (ICD), who underwent ventricular stimulation for evaluation of syncope, non-sustained VT, and/or risk-stratification prior to primary prevention ICD implantation. 12-lead ECGs were converted into vectorcardiograms and SVG magnitude (SVGmag) and direction (azimuth and elevation) were calculated. Odds of inducible VA were regressed using logistic models.

Results: Among 143 patients (median age 66, 80% male, median LVEF 47%, 52% myocardial infarction), 34 (23.8%) had inducible VAs. Inducible patients had lower median LVEF (38 vs 50%, p<0.0001), smaller SVGmag (29.5 vs 39.4mV*ms, p=0.0099), and smaller cosine SVG azimuth (cosSVGaz) (0.64 vs 0.89, p=0.0007). When LVEF, SVGmag, and cosSVGaz were dichotomized at their medians, there was a 39-fold increase in adjusted odds (p=0.002) between patients with all low LVEF, SVGmag, and cosSVGaz (65% inducible), compared to patients with all high LVEF, SVGmag, and cosSVGaz (4% [n=1] inducible). After multivariable adjustment, SVGmag, cosSVGaz, and sex, but not LVEF or other characteristics, remained associated with inducible VAs.

Conclusion: Assessment of electrical heterogeneity via SVG, which reflects abnormal electrophysiological substrate, adds to LVEF and identifies patients at high and low risk of inducible VA at EPS.

Keywords: Spatial ventricular gradient; electrophysiology study; risk stratification; vectorcardiogram; ventricular stimulation.