Initial experience with the extravascular implantable cardioverter-defibrillator: Workflow, feasibility and safety

Implantable cardioverter-defibrillators (ICDs) are among the most effective interventions for the prevention of sudden cardiac death. However, traditional transvenous systems are associated with venous access and intracardiac lead complications. Subcutaneous ICDs (S-ICD), which were developed to overcome these complications, are unable to provide anti-tachycardia pacing (ATP) or pause prevention pacing. The extravascular ICD (EV-ICD) is a recent technological innovation designed to mitigate these limitations by enabling cardioversion, defibrillation and pacing without entering the central venous system. Our aim was to assess the initial experience with the new EV-ICD system, as a valid alternative to transvenous ICD and S-ICDs, including patient selection, implantation technique, procedure feasibility and safety, functional parameters, and immediate clinical outcomes.

We conducted an observational study of all patients who underwent EV-ICD implantation between November 2024 and June 2025 at two centers. Demographic, clinical, imaging, pharmacologic and procedural data were analyzed.

A total of 11 patients were included, with a mean age of 36.3 years (range 19-59); 27% were female. Main diagnoses included hypertrophic cardiomyopathy (n=3), left ventricular non-dilated cardiomyopathy (n=3), dilated cardiomyopathy (n=2), Brugada syndrome (n=1), polymorphic ventricular tachycardia (n=1) and arrhythmogenic right ventricular cardiomyopathy (n=1). There were no procedural or peri-procedural complications. The mean procedure duration ("skin-to-skin") was 68.2 minutes (range 60-78). Median fluoroscopy time was 3.9 minutes (range 2.5-6.2). Defibrillation threshold (DFT) testing was successful in all cases. During the follow-up, two patients received an inappropriate shock, one due to sinus tachycardia and the other due to oversensing of myopotentials.

Our initial experience with the EV-ICD confirms the feasibility and safety of the procedure. This novel system may offer an effective alternative for selected populations, especially young patients with extended life expectancy and high cumulative device exposure. The rate of inappropriate shocks remains a concern and improvements are required to reduce these events.