Similarities and Differences Between the Extravascular and the Subcutaneous Implantable Cardioverter-Defibrillator: Clinical Selection and Implantation (Part 1).

PURPOSE OF REVIEW: This review examines the two non-transvenous implantable cardioverter-defibrillator (ICD) platforms; the subcutaneous ICD (S-ICD) and the extravascular ICD (EV-ICD), providing a framework for patient selection, preimplant screening, and implantation. RECENT FINDINGS: Long-term trial and registry data confirm that the S-ICD provides reliable defibrillation without intravascular leads, with lower rates of lead failure, infection, and pneumothorax compared to transvenous systems. The EV-ICD, utilizing a substernal lead, has demonstrated effective defibrillation and anti-tachycardia pacing in approximately 77% of episodes, while offering pause-prevention pacing in a smaller pulse generator with greater projected longevity. Device selection should be individualized based on pacing requirements, prior sternotomy status, and anticipated arrhythmia substrate. The S-ICD remains the only option after sternotomy, while the EV-ICD extends the non-transvenous paradigm by integrating anti-tachycardia and pause-prevention pacing. Together, these devices offer complementary solutions for patients who do not require chronic pacing or resynchronization therapy.