Electroanatomic mapping-guided localization of alternative right ventricular septal pacing sites in children

Background: Alternative right ventricular (RV) sites (RVAPS) have been proposed to prevent or reduce RV pacing-induced left-ventricular (LV) dysfunction. Nonfluoroscopic 3D electroanatomic mapping systems (EAM) have been developed to guide cardiac catheter navigation and reduce fluoroscopy during electrophysiological procedures or pacemaker implantations. Aim: The aim of the study was to compare the results of EAM-guided permanent pacemaker implantation aiming at RVAPS with conventional fluoroscopic-guided implantation in RV apex (RVA) in children and adolescents. Methods: A prospective, randomized analysis was performed on children/adolescents with complete atrioventricular block (CAVB) who underwent EAM-guided pacemaker and transvenous leads implantation into RVAPS (EAM-RVAPS) or conventional, fluoroscopic-guided implantation into RV apex (RVA). In EAM-RVAPS, a pacing map guided the implantation of ventricular leads in septal sites with narrower QRS. After implantation, LV contractility (ejection fraction [EF], Global Longitudinal Strain [GLS]) and synchrony were evaluated at 1–12 months. Results: Twenty-one pediatric patients with CAVB, with (six patients) or without structural heart diseases, aged 4–16 (median 10.5) years, were divided in two groups: EAM-RVAPS (11 patients, four dual-chamber/DDD, seven single-chamber/VVIR pacemakers) and RVA (10 patients, one DDD/nine VVIR). The two groups did not show significant differences for preoperative parameters. EAM-RVAPS showed: preserved LVEF and synchrony (not significantly different than RVA), significantly lower GLS and radiation doses/exposures, in spite more complex procedures, significantly longer procedure times and narrower paced QRS than RVA. Conclusions: EAM-guided procedures have been useful to reduce radiation exposure and to localize RVAPS with narrower paced QRS and lower GLS than RVA.