Implantable Cardioverter-Defibrillators in Children: A 14-Year Population-Based Study

Implantable cardioverter-defibrillator (ICD) therapy in children, particularly for primary prevention, remains under investigation, with limited data from less affluent European countries. With increasing use of fully subcutaneous (S-ICD) and extravascular (EV-ICD) systems, we analyzed epidemiology, indications, complications, and outcomes in pediatric ICD recipients at our tertiary center.

This retrospective, population-based, nationwide, single-center study consecutively analyzed medical records from 2012 to 2025. Patients aged 0-18 years who underwent ICD implantation were included. Kaplan-Meier analyses were performed for shock-free and mortality endpoints.

Forty-nine patients were included, corresponding to an estimated national incidence of approximately one ICD implantation per 22 000 live births. ICDs were predominantly implanted for secondary prevention (80%). Long QT syndrome (32%) and hypertrophic cardiomyopathy (22%) were the most frequent diagnoses. During 207 patient-years of follow-up (median follow-up 4 years), appropriate ICD shocks occurred in 27% of patients exclusively in the secondary prevention group. No appropriate therapies occurred in the primary prevention group despite higher overall mortality. Inappropriate shocks occurred in 22% of patients. Device-related major complications affected 17% of implanted systems. Median transvenous ICD battery longevity was 6.5 years. Overall mortality was 6%, all related to underlying structural heart disease, with no ICD-related deaths. S-ICDs demonstrated a favorable acute and mid-term safety profile in patients without pacing requirements.

Pediatric ICD therapy is limited by substantial device-related morbidity and imperfect risk stratification for primary prevention. The emerging S-ICD and EV-ICD systems represent promising, less invasive alternatives for selected pediatric patients.