Introduction. During left bundle branch area pacing (LBBAP) lead implantation, intermittent monitoring of unipolar pacing characteristics validates LBB capture and can detect septal perforation. We aimed to demonstrate that continuous uninterrupted unipolar pacing from an inserted lead stylet (LS) is feasible and facilitates LBBAP implantation. Methods. Thirty patients (mean age 76 ± 14 years) were implanted with stylet-driven pacing lead (Biotronik Solia S60). In 10 patients (validation-group) conventional, interrupted implantation was performed, with comparison of unipolar pacing characteristics between LS and connector-pin (CP)-pacing after each rotation step. In 20 patients (feasibility-group) performance and safety of uninterrupted implantation during continuous pacing from the LS were analyzed. Results. In the validation-group, LS and CP-pacing impedances were highly correlated (R2=0.95, p<0.0001, bias 12±37Ω). Pacing characteristics from LS and CP showed comparable sensed electrograms and paced QRS morphologies. In the feasibility-group, continuous LS-pacing allowed beat-to-beat monitoring of impedance and QRS morphology to guide implantation. This resulted in successful LBBAP in all patients, after a mean of 1±0 attempts, with mean threshold 0.81 ± 0.4V, median sensing 6.5mV [IQR 4.4-9.5] and mean impedance 624 ± 101Ω, and positive LBBAP-criteria with median paced QRS duration 120ms [IQR 112-152ms] and median pLVAT 73ms [IQR 68-80.5ms]. No septal perforation occurred. Conclusion. Unipolar pacing from the LS allows accurate determination of pacing impedance and generates similar paced QRS morphologies and equal sensed electrograms, compared to CP pacing. Continuous LS pacing allows real-time monitoring of impedance and paced QRS morphology, which facilitates a safe and successful LBBAP lead implantation.

Abstract: Conventional stylet-driven leads with extendable helix can be implanted successfully for Left Bundle Branch Area Pacing (LBBAP) with a low acute complication rate. However, removal and repositioning techniques of these leads haven’t been yet described. We report 2 cases in which lead repositioning after a first unsuccessful attempt to LBBAP was associated with fracture of the helix rotating mechanism and failure to fully extract the pacing lead.

Biventricular pacing (BVP) has been demonstrated to improve functional outcomes and mortality of patients with symptomatic heart failure, reduced LVEF and wide QRS. Unfortunately, difficult coronary sinus anatomy can limit left ventricular lead placement. In such clinical situation, His Bundle Pacing (HBP) and Left Bundle Branch Area Pacing (LBBAP) have recently appeared as attractive alternatives to BVP. We describe the case of a patient with an indication for Cardiac Resynchronization Therapy (CRT) and AV node ablation, where left ventricular lead implantation and corrective HBP failed. LBBAP allowed for electrical and echocardiographic resynchronization with significant functional improvement.