Amplitude of QRS complex within initial 40 ms in V2 (V2QRSi40): Novel electrocardiographic criterion for predicting accurate localization of outflow tract ventricular arrhythmia origin

Abstract Background The initial depolarization vector of outflow tract (OT) ventricular arrhythmia (VA) varies in different origins, which may help to predict OT-VA origin more accurately. Objective To develop a more accurate electrocardiographic (ECG) criterion for differentiating between left and right OT-VA origins. Methods We studied 275 patients with successful ablation in the right ventricular OT (RVOT; n =207) or left ventricular OT (LVOT; n =68) in development cohort. The amplitude of QRS complex within initial 40 ms (QRSi40) in precordial leads were measured. A novel criterion for identifying the OT-VAs origin was developed based on development cohort. Predictive performance of novel criterion was further validated by comparing with previous ECG criteria (V2S/V3R index, V2 transition ratio and TZ index) in validation cohort with 107 patients (RVOT: 75, LVOT: 32). Results The QRSi40 of identical precordial leads were significantly greater in LVOT group than RVOT group (P Conclusion The V2QRSi40 is a novel and accurate ECG criterion to predict OT-VAs origin, which also outperforms previous criteria.