Acute success, stability and safety of left bundle branch area pacing with steerable catheter and stylet-driven leads: A single center experience

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND/INTRODUCTION: Right ventricular apical pacing is associated with adverse outcomes and there is an increasing preference to perform conduction system pacing as it allows for more physiological left ventricular activation. His-bundle pacing is known to be technically challenging and results in higher pacing thresholds and increased rates of lead dislodgement. Left bundle branch area pacing (LBBAP) is an emerging alternative form of conduction system pacing. PURPOSE: We aim to study the acute success rates, short-term stability and safety using steerable catheter and stylet-driven (SD) leads for the purpose of LBBAP. METHODS: 40 consecutive patients who underwent LBBAP with steerable catheter and SD leads in our center from August 2021 to November 2022 were included in this series. Patients’ demographics, pacing indications, baseline QRS morphologies and duration and left ventricular ejection fraction (LVEF) were analysed. Acute success was defined as achieving stimulation to LV activation time (Stim-LVAT) ≤75ms or incomplete right bundle branch paced morphology in V1 [1, 2]. We also reported any left bundle branch (LBB) potential (if present) and the V6-V1 interpeak interval. All lead parameters and complications in the immediate (1 day) and short-term (1 week and 3-6 months) timeframe were evaluated. RESULTS: 40 patients' age (mean 72.75), gender (male 52.5%), body mass index (mean 24.15) and LVEF (mean 52.75%) were analysed. Pacing indications included sinus nodal dysfunction (25%), atrioventricular block (70%), heart failure with failed cardiac resynchronisation therapy (CRT) (2.5%) and atrial fibrillation (AF) requiring atrioventricular node ablation (2.5%). We achieved an acute success rate of 87.5% (5% with left ventricular septal pacing, 5% converted to conventional right ventricular septal pacing, and 2.5% converted to CRT). Reasons for failure to achieve successful LBBAP include persistent left superior vena cava, high pacing thresholds or inability to burrow lead into the septum for acceptable V1 morphology and Stim-LVAT due to resistance encountered during turning of the lead. 51.43% patients of the successful LBBAP patients had LBB potential present and/or interpeak interval >33ms [3]. Immediate and short-term lead parameters were stable and acceptable in all cases. There were no complications (such as lead dislodgement, rise in lead impedance or threshold) reported during the acute and short-term follow-up. CONCLUSION: LBBAP is successful in 87.5% of our cases with use of steerable catheter deploying stylet-driven leads and is proven to be a safe and feasible method for conduction system pacing. Incremental experience with the delivery tools will further improve successful implantation. Longer term follow-up of these patients is needed to determine the long-term safety and stability of LBBAP using steerable catheter and stylet-driven leads. [Figure: see text] [Figure: see text]