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. 2025 Nov 25:S0735-1097(25)09920-6.
doi: 10.1016/j.jacc.2025.10.020. Online ahead of print.

Inappropriate Shocks From Subcutaneous vs Transvenous Implantable Cardioverter-Defibrillators: Individual Participant Data Meta-Analysis of Randomized Trials

Alexander P Benz  1 , Louise R A Olde Nordkamp  2 , William F McIntyre  3 , Leonard A Dijkshoorn  2 , Blandine Mondésert  4 , Jamil Bashir  5 , Timothy R Betts  6 , Martin C Burke  7 , Mikhael F El-Chami  8 , Laura Heenan  3 , Andrew D Krahn  5 , Jürgen Kuschyk  9 , Shun Fu Lee  3 , Reinoud E Knops  2 , Jeff S Healey  3 ; PRAETORIAN and ATLAS Investigators
Affiliations

Inappropriate Shocks From Subcutaneous vs Transvenous Implantable Cardioverter-Defibrillators: Individual Participant Data Meta-Analysis of Randomized Trials

Alexander P Benz et al. J Am Coll Cardiol. .

Abstract

Background: The PRAETORIAN (Prospective Randomized Comparison of Subcutaneous and Transvenous Implantable Cardioverter Defibrillator Therapy) and ATLAS (Avoid Transvenous Leads in Appropriate Subjects) trials demonstrated a reduction in lead-related complications with subcutaneous compared with transvenous implantable cardioverter-defibrillators (ICDs) in patients with standard ICD indications. However, they were not individually powered to assess differences in inappropriate shock.

Objectives: The aims of this study were to compare the rates of a first inappropriate shock between subcutaneous and transvenous ICDs and to explore the underlying causes.

Methods: An individual participant data meta-analysis of PRAETORIAN and ATLAS was performed, using Cox regression models stratified by trial. The primary endpoint was time to first inappropriate shock.

Results: The pooled modified intention-to-treat population included 1,342 patients (median age 58 years, 21.8% women, 77.7% with primary prevention indications) who had been randomized to subcutaneous or transvenous ICDs. A proprietary algorithm aimed at reducing inappropriate shock was activated at baseline or at some point during follow-up in 77.1% of patients with subcutaneous ICDs. During a median follow-up period of 3.5 years, a first inappropriate shock occurred more frequently in patients randomized to subcutaneous compared with transvenous ICDs (2.5 vs 1.5 per 100 patient-years; HR: 1.61; 95% CI: 1.06-2.45; P = 0.03). Patients with subcutaneous ICDs had a higher hazard of first inappropriate shock due to cardiac oversensing (HR: 15.07; 95% CI: 3.60-63.15; P < 0.001) and electromagnetic interference or myopotentials (HR: 8.19; 95% CI: 1.88-35.64; P = 0.005) but a lower hazard of first inappropriate shock due to atrial arrhythmia (HR: 0.37; 95% CI: 0.19-0.71; P = 0.003).

Conclusions: Although first inappropriate shocks were infrequent overall, they were more common with subcutaneous ICDs. First inappropriate shocks due to cardiac oversensing and electromagnetic interference were more common with subcutaneous ICDs, while first shocks due to atrial arrhythmia were more common with transvenous ICDs.

Keywords: S-ICD; TV-ICD; cardiac implantable electronic device; cardioversion; defibrillation; sudden cardiac death.

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Conflict of interest statement

Funding Support and Author Disclosures The PRAETORIAN and ATLAS trials were funded by Boston Scientific. Dr Benz has received honoraria from AstraZeneca and Bristol Myers Squibb; and has participated in an educational program supported by Boston Scientific (Fellowship Herzrhythmus). Dr McIntyre has received honoraria from Trimedics, AtriCure, and iRhythm; and has received research grants from Trimedics. Dr Mondésert has received honoraria from Abbott Laboratories, Bayer, Biotronik, Boston Scientific, Baylis, Cook Medical, Merit Medical, Medtronic, Milestone Pharma, Pfizer, and Philips; and has received a research grant from Boston Scientific. Dr Burke has received honoraria and research grants from Boston Scientific and AtaCor Medical; and holds an equity position in AtaCor Medical. Dr El-Chami has received honoraria from Medtronic and Boston Scientific. Dr Knops has received honoraria and research grants from Abbott Laboratories, Boston Scientific, Medtronic, and Cairdac; and has stock options in AtaCor Medical. Dr Healey has received honoraria from Bayer, Boston Scientific, Bristol Myers Squibb/Pfizer, Medtronic, and Servier; and has received research grants from Boston Scientific and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.

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