Subcutaneous and Transvenous ICDs: an Update on Contemporary Questions and Controversies.

Changes in sensing algorithms and S-ICD programming have significantly decreased inappropriate shock rates. Avoiding fat below the S-ICD coil and can is key for reducing the defibrillation threshold. While S-ICD battery and electrode failures have resulted in recalls, system components remain commercially available since failure rates are low and no other similar devices are available. The S-ICD is a good alternative to the TV-ICD for many patients, and particularly in light of recently developed device algorithms and improvements in implant technique. Future research will need to better understand: the impact of S-ICD electrode and battery failures and the potential for integrating leadless pacing into a modular S-ICD platform.