Abstract 8864: Left Bundle Branch Area Pacing is Non-Inferior to His Bundle Pacing in Achieving Physiologic Repolarization and T-Wave Memory Resolution

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Introduction: We have previously reported that His bundle pacing (HBP) results in more physiologic ventricular repolarization as compared to conventional biventricular pacing. Left bundle branch area pacing (LBAP) is increasingly used as the preferred modality of physiologic pacing due to ease of implantation and low long-term pacing thresholds. LBAP and HBP are comparable in terms of achieving physiologic left ventricular (LV) depolarization. However, their effects on ventricular repolarization have not been assessed. Established ECG markers of arrhythmic risk can be used to compare ventricular repolarization across these two modalities of physiologic pacing. Hypothesis: LBAP is not inferior to HBP in its effects on ventricular repolarization and T-wave memory resolution. Methods: The following parameters were analyzed in patients with HBP (n = 34) and LBAP (n = 16) from post-implant ECGs: 1) QTc: QT corrected using Bazett’s formula in lead V5, and if not measurable, in V4 or V6 2) QTc Dispersion: Longest minus shortest QTc from precordial leads 3) Tp-Te Transmural: T-peak minus T-end in same lead as 1) 4) Tp-Te Total: Earliest T-peak minus latest T-end from all precordial leads 5) Tp Dispersion: Latest minus earliest T-peak from precordial leads To analyze T-wave memory resolution, QRS-T angles were compared using ECGs within 10 days of and after ≥ 25 days post implant. Results: See tables. Median time from implant to 1st ECG for both groups was ≤1 day. None of the repolarization parameters were significantly different in HBP vs. LBAP groups. Conclusion: All repolarization markers of arrhythmic risk were similar in HBP vs. LBAP. Both modalities showed similar effects on T-wave memory resolution. These data suggest that LBAP, in addition to achieving physiologic LV depolarization, is not inferior to HBP in achieving physiologic ventricular repolarization. These observations further support the increasing use of LBAP as the preferred modality for physiologic pacing.