[The subcutaneous cardioverter-defibrillator: When less is more]

Area of Science:

• Cardiology
• Medical Devices
• Electrophysiology

Background:

• Defibrillator therapy, including implantable cardioverter-defibrillators (ICDs), has significantly advanced sudden cardiac death prevention.
• Transvenous ICD (TV-ICD) systems are associated with specific periprocedural and long-term complications.
• The subcutaneous ICD (S-ICD) system offers a transvenous-free approach, potentially mitigating these risks and eliminating the need for fluoroscopy during implantation.

Purpose of the Study:

• To evaluate the efficacy and safety of the S-ICD system.
• To compare S-ICD performance against traditional TV-ICD systems.
• To identify patient populations and clinical scenarios where S-ICD is particularly suitable.

Main Methods:

• Multicenter studies and registries were utilized to assess S-ICD performance.
• Cardiac rhythm detection is managed through three potential vectors, with automatic selection of the optimal vector.
• The S-ICD system is capable of delivering high-energy shocks and provides postshock pacing.

Main Results:

• The S-ICD system demonstrated efficacy and safety profiles equal to or better than TV-ICD systems in multicenter studies and registries.
• Initial challenges such as inappropriate shocks and infections have been addressed through standardized implantation techniques, operator experience, and algorithm modifications.
• The S-ICD is considered a viable option for patients with challenging anatomy or a history of infection.

Conclusions:

• The S-ICD is a suitable option for most patients indicated for defibrillator therapy, excluding those requiring pacing, cardiac resynchronization therapy (CRT), or those with specific ventricular tachycardia rates or negative screening results.
• The S-ICD system has received regulatory approval (CE in 2009, FDA in 2012) and is recognized for reimbursement in some healthcare systems.
• Ongoing advancements in implantation techniques and algorithms continue to enhance the performance and safety of the S-ICD system.