Po-01-048 factors influencing subcutaneous implantable cardioverter defibrillator screening success in paediatric population: a tertiary hospital experience

Implantable cardioverter defibrillators (ICD), used to reduce risk from life threatening ventricular arrhythmia, are important treatments. Subcutaneous ICD (SICD) offers a lower risk of endocarditis, lead fracture and vascular complication. Screening is essential to identify the appropriate candidates and reduce inappropriate shocks, however there are limited data available in the paediatric population. To assess the incidence and associated characteristics of SICD screen failure, and the incidence of inappropriate shocks in a paediatric population. All patients screened for SICD from June 2016 to November 2022 were included. Screening failures were identified from supine, standing and exercise in both left and right sternal positions. Those who passed at least two vectors in all conditions were offered an SICD. The incidence of inappropriate shocks on follow up was assessed. From 74 screened patients (baseline characteristics Table 1), 58 (78%) passed supine and standing and 51(69%) on exercise screening. 59 (67%) had Hypertrophic Cardiomyopathy (HCM), 17 (23%) Inherited arrhythmias (IA) and 8 (11%) Other Cardiomyopathies (OC). Overall, 60(81%) had a primary prevention indication. Of the 45 (61%) who passed screening on the left supine, all passed when standing and 43 (96%) passed on exercise. Those screened on the right, 18 (55%) passed supine, 16(88%) of these passed standing and 14(87%) passed on exercise. Those that failed were younger and had HCM (passed vs failed, age 14±2.6 vs 12±3.7, p=0.009, HCM 56% vs 87%, p=0.008). IA patients were more likely to pass (pass vs failed, 35% vs 8%, p=0.02). Weight, height and BMI did not impact on the failure rate (Table 1). Overall, 40 (78%) had an SICD implanted with a mean follow up 21±15 months. Four patients had inappropriate shocks; One for air in the header and three for T wave oversensing. Those who had T wave oversensing had left sided lead implants, two had HCM and one had AI. In this population the screen failure rate for SICD was high, particularly in younger patients with HCM. The addition of exercise further excluded patients however, the number was small. There was no link between weight, height and BMI and screen failure. The incidence of inappropriate shocks was low.Tabled 1Table 1 – Characteristics of patients who passed and failed Subcutaneous Internal Cardioverter Defibrillator ScreeningCharacteristicsPassed (n=51)Failed (n=23)p-valueAge, years mean (SD)14 ± 2.612 ±3.7p=0.009Sex F(%)17 (34)6 (26)p=0.6Weight kg, mean (SD)57 ±16.953 ±(22)p=0.34Height cm mean (SD)156 ±29.6155 ±17.8p=0.88BMI kg/m2 mean (SD)23 ± 10.421 ± 5.5p=0.39HCM n (%)29 (56)20 (87)p=0.008Inherited n (%)15 (29)2 (8)p=0.02Other Cardiomyopathy n (%)7 (14)1 (4)p=0.26 Open table in a new tab