Safety and Efficacy of the Extravascular Implantable Cardioverter-Defibrillator (EV ICD) in Japanese Patients　― Final Results From the EV ICD Japan Study ―

Background: The extravascular implantable cardioverter-defibrillator (EV ICD) has proven efficacy and a low complication rate in global populations, but data from Japanese patients is limited. We report the safety and efficacy of the EV ICD system in a Japanese cohort through 12 months of follow-up. Methods and Results: Patients from Japan with a Class I or IIa indication for a single-chamber ICD were enrolled and implanted with the EV ICD system. Defibrillation success was determined following implant. System programming changes, device electrical performance, freedom from major system- or procedure-related complications through 12 months post-implant, and follow-up status at all visits were assessed. From February to September 2023, 14 patients (12 males, 2 females) were enrolled and successfully implanted across 2 sites (age: 53.6±14.7 years; left ventricular ejection fraction: 52.6±15.6%; secondary prevention: 42.9%). Defibrillation testing was successful in all patients (14/14, 100%). At 2 weeks and 12 months, freedom from major system- and/or procedure-related complications was 92.9% and 85.7%, respectively. One patient received 7 appropriate shocks that were successful in terminating the arrhythmia. There were no inappropriate shocks delivered, and a single inappropriate antitachycardia pacing therapy was delivered through follow-up. Conclusions: The EV ICD system was safely implanted and effective at terminating both induced and spontaneous ventricular arrhythmias in a small cohort of Japanese patients.