Electrocardiographic (ECG) criteria have been proposed to localize the site of origin (SOO) of outflow region ventricular arrhythmias (VAs). Many factors influence the QRS morphology of VAs and may limit the accuracy of these criteria.
To assess the accuracy of ECG criteria that differentiate right from left outflow region VAs and localize VAs within the aortic sinus of Valsalva (ASV).
One hundred one patients (mean age 52±16 years; 54% female) undergoing catheter ablation of right ventricular outflow tract (RVOT) or ASV VAs with left bundle branch block, inferior axis morphology were studied. ECG measurements including V transition ratio, transition zone index, R wave duration index, R/S amplitude index, VS/VR index, V QRS morphology, R-wave amplitudes in the inferior leads were tabulated for all VAs. Comparisons were made between the predicted SOO using these criteria and the successful ablation site.
Patients had successful ablation of 71 RVOT and 38 ASV VAs. For differentiation of RVOT from ASV VAs, the positive predictive values and negative predictive values for all tested ECG criteria ranged from 42-75% and 71-82% respectively, with the VS/VR index having the greatest AUC of 0.852. Morphologic QRS criteria in V – V did not localize ASV VAs. The maximal R-wave amplitude in the inferior leads was the sole criterion demonstrating a significant difference between right ASV, right-left ASV commissure and left ASV sites.
Electrocardiographic criteria for differentiating right from left ventricular outflow region VAs and for localizing ASV VAs have limited accuracy.

Copyright © 2021. Published by Elsevier Inc.