3D-GUIDED SELECTIVE RIGHT VENTRICULAR SEPTAL PACING PRESERVES VENTRICULAR SYSTOLIC FUNCTION AND SYNCHRONY IN PAEDIATRIC PATIENTS.

ABSTRACT BACKGROUND Non-fluoroscopic 3D-electroanatomic mapping systems (EAMs) have been developed to guide cardiac catheter navigation and reduce fluoroscopy. Selective right ventricular (RV) septal pacing could prevent pacing-induced left ventricular (LV) dysfunction. OBJECTIVE Aim of the study was to seek out if EAM-guided selective RV septal pacing preserves LV contractility/synchrony in pediatric patients with complete atrioventricular block (CAVB) and no other congenital heart defects. METHODS Prospective analysis of children/adolescents who underwent EAM-guided selective RV pacing. A 3D-pacing map guided ventricular lead implantation in septal sites with narrow paced QRS. Serial echocardiograms were obtained following the pacemaker implantation to monitor for the function (volumes, ejection fraction [EF], global longitudinal/circumferential strain) and synchrony (interventricular mechanical delay, septal to posterior wall mechanical delay, systolic dyssynchrony index). Data are reported as median (25th-75th percentile). P RESULTS Thirty-two CAVB patients (11 with a previous pacing system), aged 9.8 (7.0-14.0) years, underwent selective RV septal pacing (13 DDD, 19 VVIR pacemakers) in midseptum (22 patients), para-Hisian ( 7 ), RV outflow tract ( 3 ) with narrow paced QRS [110 (100-120) ms], and low radiation exposure. Follow-up over 24 (5-33) months showed preserved LV function and synchrony, without significant differences between pacing sites (midseptum-paraHisian) and mode (VVIR-DDD). EF decreased after implantation in patients without previous pacing, although values were mainly within normal limits. Three para-Hisian patients underwent early lead repositioning. CONCLUSION EAM-guided selective RV septal pacing is a feasible technique associated with preserved LV systolic function and synchrony and low radiation exposure in pediatric patients with CAVB.