Three-dimensional-mapping-guided permanent conduction system pacing in paediatric patients with congenitally corrected transposition of the great arteries.

Aims: In congenitally corrected transposition of the great arteries (CCTGA) the right ventricle (RV) is systemic. Atrioventricular block (AVB) and systolic dysfunction are frequently observed. Permanent pacing of the subpulmonary left ventricle (LV) may worsen RV dysfunction. The aim of this study was to seek out if LV conduction system pacing (LVCSP) guided by three-dimensional-electroanatomic mapping systems (3D-EAMs) can preserve RV systolic function in paediatric CCTGA patients with AVB.

Methods And Results: Retrospective analysis of CCTGA patients who underwent 3D-EAM-guided LVCSP. Three-dimensional-pacing map guided lead implantation towards septal sites with narrower paced QRS. Electrocardiograms (ECGs), echocardiograms, and lead parameters (threshold, sensing, and impedance) were compared at baseline (pre-implantation) and at 1-year follow-up. Right ventricle function was evaluated by 3D ejection fraction (EF), fractional area change (FAC), RV global longitudinal strain (GLS). Data are reported as median (25th-75th centiles). Seven CCTGA patients aged 15 (9-17) years, with complete/advanced AVB (4 with prior epicardial pacing), underwent 3D-guided LVCSP (5 DDD, 2 VVIR). Baseline echocardiographic parameters were impaired in most patients. No acute/chronic complications occurred. Ventricular pacing was >90%. At 1-year follow-up QRS duration showed no significant changes compared with baseline; however, QRS duration shortened in comparison with prior epicardial pacing. Lead parameters remained acceptable despite ventricular threshold increased. Systemic RV function was preserved: FAC and GLS improved significantly, and all patients showed normal RV EF (>45%).

Conclusion: Three-dimensional-EAM-guided LVCSP preserved RV systolic function in paediatric patients with CCTGA and AVB after short-term follow-up.