B-PO04-150 SPATIAL VENTRICULAR GRADIENT IS ASSOCIATED WITH INDUCIBLE VENTRICULAR ARRHYTHMIAS DURING ELECTROPHYSIOLOGY STUDY

Abstract

The spatial ventricular gradient (SVG) is a vectorcardiographic measure of global electrical heterogeneity that has been associated with sudden cardiac death (SCD) in the general population. The association between SVG and inducibility of ventricular tachycardia (VT) or ventricular fibrillation (VF) during electrophysiology study (EPS) is unknown. To test the association between SVG and inducible VT/VF during EPS. We performed a retrospective study of patients presenting for EPS for evaluation of syncope or risk stratification of SCD prior to primary prevention ICD implantation between 6/2016-12/2020. 12-lead ECGs prior to EPS were converted to vectorcardiograms, and SVG magnitude, azimuth (direction in the XZ transverse plane), and elevation (direction in the XY frontal plane) were calculated. SVG components were dichotomized above and below their median values. Variables were compared with the t-test except for SVG azimuth (a circular variable), which was compared with the Mardia-Watson-Wheeler test. The odds of inducible VT/VF were regressed using a logistic model. Among 100 patients presenting for EPS (mean age 65.5 ± 12.1 y, 77% male, mean LVEF 46 ± 12 %), 20 had inducible VT/VF. Patients with inducible VT/VF had lower LVEF (40 ± 8 vs. 48 ± 12 %, p=0.017) and more posteriorly directed SVG azimuth (25.3 vs. 15.2 deg, p=0.01) than those who were non-inducible. Unadjusted logistic regression demonstrated that the OR for inducible VT/VF was 3.86 (95% CI 1.28-11.64, p=0.017) for SVG magnitude < 41.2 mv*ms and 8.07 (95% CI 2.19-29.78, p=0.002) for absolute SVG azimuth > 46.6 deg. SVG elevation, QRS duration, and QT interval were not associated with VT/VF. After adjustment for age, gender, LVEF, and prior MI, both SVG magnitude and absolute azimuth remained significantly associated with inducible VT/VF: adjusted OR for inducible VT/VF was 6.66 (95% C1.82-24.43, p=0.004) for SVG magnitude < 41.2 mv*ms and 7.53 (95% CI 1.81-31.35, p=0.005) for absolute SVG azimuth > 46.6 deg. Smaller SVG magnitude and more extreme anterior or posterior SVG azimuth are associated with inducible VT/VF. SVG warrants prospective studies for risk stratification in patients undergoing EPS.