Extravascular implantable cardioverter-defibrillators in children: case series and systematic review

Background

Extravascular implantable cardioverter-defibrillators (EV-ICDs) and other non-transvenous systems are attractive options for paediatric patients in whom the use of transvenous leads is constrained by body size, cardiac anatomy, and concerns about long-term lead-related complications.

Although EV-ICDs have demonstrated safety and efficacy in adult pivotal trials, paediatric patients were excluded from these studies, and available data in children are limited to small case series and isolated reports, and comprehensive synthesis of the existing experience is lacking.

Aim

To describe a case series and systematically review the literature on EV-ICD use in paediatric patients.

Methods

A retrospective, single-centre case series was conducted including all consecutive patients aged <18 years who received an EV-ICD between 2024 and 2025. Indications, patient and procedural characteristics, defibrillation testing results, device parameters and complications were obtained from electronic medical records.

In parallel, we systematically searched electronic databases (MEDLINE, Scopus, and Web of Science) up to November 2025 for studies reporting EV-ICD use in patients aged <18 years, with data extracted on implantation feasibility, safety, and efficacy outcomes.

Results

We report two paediatric patients who underwent uncomplicated EV-ICD implantation with successful defibrillation testing. Patient 1: A 13-year-old girl (52 kg) with non-obstructive hypertrophic cardiomyopathy (MYBPC3 mutation; HCM Risk-Kids 8.4%) received a primary-prevention EV-ICD. She experienced two inappropriate shocks at 2 months due to P-wave oversensing, which resolved after sensing vector reprogramming, with no further events over 7-months of follow-up. Patient 2: A 17-year-old boy (48 kg) with idiopathic ventricular fibrillation after aborted sudden cardiac death received a secondary-prevention EV-ICD. Follow-up at 16 months was uneventful, with no shocks or device-related complications.

The systematic review identified 8 published articles including 33 paediatric patients, predominantly adolescents, in whom implantation success was 100% (see Table 1). Defibrillation testing, when performed, was uniformly successful, and reported complications were infrequent, mainly involving lead repositioning and inappropriate shocks. Follow-up was limited to a maximum of 9 months, limiting assessment of long-term device performance and late complications.

Conclusion

Overall, the available evidence—though limited to small, heterogeneous case series with short follow-up, suggests that EV-ICD implantation in paediatric patients is technically feasible with consistently high acute success and low short-term complication rates. Robust long-term data are still needed to understand durability, growth-related effects, and late device performance in this population.For image description, please refer to the figure legend and surrounding text.