Left bundle-branch area pacing in paediatric and congenital heart disease - a nationwide single-center experience

Abstract Background Conduction system pacing, including left bundle branch area pacing (LBBAP), provides a physiological alternative to conventional right ventricular pacing by preserving native ventricular activation. While LBBAP has shown favourable results in adults, data in paediatric and congenital heart disease (CHD) populations remain limited. Evidence is primarily from small, single-centre studies with short follow-up. The long-term safety and efficacy in these patients are still not well established. Purpose To evaluate the feasibility, procedural characteristics, and follow-up data of LBBAP in paediatric and CHD patients, with a focus on electrical parameters, ECG, and echocardiographic findings. Methods We performed a retrospective, single-centre analysis of paediatric and CHD patients who underwent LBBAP implantation between November 2023 and September 2025 in our national tertiary referral center. Procedural data were collected during implantation, follow-up data included device interrogation, ECG, and echocardiography. Primary endpoints were procedural success, pacing and sensing parameters, QRS duration, LVEF, and complications. Results Thirteen patients (mean age 24±15.9 years; 53.8 % male) underwent LBBAP. Our CHD patients were divers, including tetralogy of Fallot (n=1), double outlet right ventricle (n=1), congenital aortic or subaortic stenosis (n=2), ventricular septal defect (n=2), atrial septal defect (n=2) and AVSD (n=1). Indications were congenital AV block (n = 5), failed CRT (n = 2), postoperative conduction disturbance (n = 3), epicardial pacemaker dysfunction (n = 1), late postoperative AV block in tetralogy of Fallot (n = 1), and as part of a pace-and-ablate strategy prior to AV node ablation (n = 1). LBBAP was the primary pacing strategy in 69.2 % of cases. Successful implantation was achieved in 12 of 13 patients; in one case, deep septal pacing was performed due to failure of selective left bundle capture. Mean procedure and fluoroscopy times were 91.3 ± 48.9 min and 12.0 ± 10.4 min, respectively. The acute paced QRS duration was 97 ± 7 ms (V6 RWPT 75 ± 8 ms; V6–V1 interpeak interval 41 ± 7 ms). At a mean follow-up of 13.1 ± 7.3 months, pacing and sensing parameters remained stable (sensing 15.2 ± 2.7 mV; impedance 518.1 ± 121.6 Ω; threshold 0.70 ± 0.25 V @ 0.4 ms). Mean paced QRS duration was 110 ± 19 ms. No major procedural or late complications occurred. LVEF remained preserved in patients without CRT indication (65 ± 13 % vs. 61 ± 15 %), while patients implanted for failed CRT demonstrated clear improvement in systolic ejection fraction. Conclusion In paediatric and ACHD patients, successful LBBAP is a feasible and safe pacing approach that maintains ventricular synchrony. Despite slightly longer procedural times, its physiological conduction pattern offers advantages over conventional right ventricular pacing by preventing pacing induced cardiomyopathy, especially in this young patient population.