Po-03-079 his-bundle pacemaker implantation in pediatrics: significant issues during short-term follow-up

In patients with AV-block (AVB), His bundle pacing (HBP) allows physiological ventricular depolarisation and may prevent pacemaker-induced cardiomyopathy. Selective and non-selective HBP is a feasible procedure in pediatric patients with and without congenital heart disease (CHD). Data on implantation and follow-up after HBP-implantation with special reference to time course of electrode parameters is limited in young patients with HPB. We analyzed the short-term course of patients < 18 years of age after HIS-Bundle pacemaker implantation (HIS-PM). Data were collected from all patients < 18 years of age who underwent HIS-PM implantation at 2 pediatric heart centers. Data of HIS-PM interrogation at implantation as well as 4 weeks, 3, 6, and 12 months after PM-Implantation were analyzed, respectively. Since 10/2020, 10 patients (8 females) with complete AVB (congenital: n=9, acquired after surgical VSD closure: n=1) underwent HIS-PM implantation. Median age at HIS-PM implantation was 13.5 (range 8.2-17.1) years, median body weight was 56.0 (range 32.1-94.0) kg. Median duration of the implant procedures was 146 (range 99-320) minutes, median fluoroscopy time was 13.4 (range 3.37-29.6) minutes, median X-ray-dosage 3420 (range 780-9060) mGycm2, respectively. Due to high ventricular pacing thresholds (> 3.5V @ 1ms) during the implantation procedure, despite extensive search for optimal location of the HIS-electrode, HBP could not be realized in 2 patients with congenital AVB. These 2 patients received conventional dual chamber pacemaker implantation. Selective HBP could be achieved in 2 patients and non-selective HBP in the remaining patients. During median follow-up of 7.8 months (range 3.8-12.9), median HIS-electrode threshold increased significantly from 0.9 V to 2 V (p=0.046) without significant changes in HIS electrode impedance. Up to now, 3/8 (37.5%) HIS-PM systems had to be revised due to infection 2.6 months after implant (n=1), ventricular threshold 3,75 V @ 1,5 ms 2 months after implant (n=1), and HIS electrode dislocation (n=1), respectively. Atrial electrode parameters remained unchanged since implantation. During short-term follow-up period, significant issues after HIS-PM implantation in pediatric patients became evident in a considerable portion of patients. Although data is still limited, these findings may limit further use of HBP in young patients.