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

## TL;DR

This study examines the use of implantable cardioverter-defibrillators in children, highlighting their use for secondary prevention and the challenges of complications and inappropriate shocks.

## Contribution

The study provides a population-based analysis of pediatric ICD use in Slovakia, emphasizing outcomes and complications in a less affluent European country.

## Key findings

- ICDs were predominantly implanted for secondary prevention, with 80% of cases.
- Inappropriate shocks occurred in 22% of patients, highlighting a clinical burden.
- S-ICDs showed a favorable safety profile in patients without pacing requirements.

## Abstract

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.

Nationwide pediatric ICD cohort from Slovakia illustrating incidence, indications, shock outcomes, and device‐related adverse events, highlighting the predominance of secondary prevention and the clinical burden of inappropriate shocks and major complications.