A valuable electrophysiological insight to distinguish right from left outflow tract ventricular arrhythmia -local activation time in the anterior intraventricular vein and distal great cardiac vein-

Abstract

Abstract Background Although several ECG criteria have been helpful to differentiate right from left outflow tract ventricular arrhythmias (OTVAs), discriminating OTVA origins especially with left bundle branch block (LBBB) is still considered challenging. Objective The aim of this study was to investigate the local activation time (LAT) in the anterior intraventricular vein (AIV) and distal great cardiac vein (d-GCV), and to identify an electrophysiological method of distinguishing right from left OTVAs. Methods We measured the LAT relative to the QRS onset of OTVAs in the AIV and d-GCV using a microelectrode with a lumen catheter in patients undergoing successful OT-VA ablation between January 2017 and July 2022 in our institution. The ECG parameters such as the V2 transition-ratio and V2S/V3R index to distinguish right-OT-VAs from left-OT-VAs with LBBB were also investigated. Results Local potentials at the AIV and/or d-GCV OTVA sites in 76 consecutive patients (mean age: 56.5±16.2 year-old, right-OTVAs:40, left-OTVAs:36) were analyzed. The LAT of the AIV/d-GCV was significantly shorter for right-OTVAs than left-OTVAs (d-GCV -26.7±26.8 vs. -2.7±21.4 msec, p<0.001, AIV -9.9±23.2 vs. 16.9±18.2 msec, p<0.001), and associated with the identification of right-OTVAs and left-OTVAs (AUC: d-GCV: 0.76 [95%CI 0.65-0.86], AIV: 0.81 [0.70-0.92]). Defining a LAT <0ms in the AIV (sensitivity: 0.74, specificity: 0.75), <-24ms in the d-GCV (sensitivity: 0.83, specificity: 0.60) as cutoff values respectively, the overall odds ratio (OR) increased more for right-OTVAs than left-OTVAs (OR; AIV: 6.7 [1.9-23.4], p=0.002, d-GCV: 7.5 [2.5-22.1], p<0.001). In the multivariate analysis, a LAT<-24ms in the d-GCV was revealed as an independent predictor certifying right-OTVA origins (OR 14.4 (2.1-95.1), p=0.006), which was superior to the V2 transition-ratio and V2S/V3R index. Conclusion The AIV/d-GCV activation time could outperform other previous ECG criteria to discriminate right-sided from left-OTVA ventricular arrhythmias with LBBB.