Retrosternal extravascular implantable cardioverter-defibrillators: a systematic review of implant characteristics, defibrillation testing, and acute safety.

Introduction: Implantable cardioverter-defibrillators (ICD) terminate potentially deadly ventricular arrhythmias in at-risk patients. Retrosternal extravascular ICDs (EV-ICD) place a lead in the mediastinal space to provide both shock and antitachycardia pacing therapy without the need for venous access. A systematic review was performed to assess acute outcomes in patients implanted with a retrosternal EV-ICD.

Methods: A query of EMBASE and MEDLINE databases was performed to identify unique retrosternal EV-ICD cohort studies published between JAN-1-2020 and JAN-31-2026. Two known retrosternal EV-ICDs were included, the market-approved Medtronic substernal EV-ICD system and investigational AtaCor intercostal EV-ICD lead. Procedure and defibrillation testing details and acute safety data were collected.

Results: Fourteen articles (n = 806 patients) met criteria for inclusion. Lead placement success was 99.6% and 97.3% while defibrillation testing success was 98.5% and 97.2% for the substernal EV-ICD system and intercostal EV-ICD lead, respectively. Periprocedural complications were manageable with a rate of 1.5% (n = 11/731) for the substernal EV-ICD system and 8.2% (n = 6/73) for the intercostal EV-ICD lead.

Conclusions: The available evidence suggests that periprocedural outcomes and acute safety of retrosternal EV-ICD systems, particularly the substernal EV-ICD system, is an effective and safe strategy that provide potentially lifesaving therapy while preserving the vasculature.Protocol registration: www.crd.york.ac.uk/prospero identifier is CRD420261328371.