Recent advances in the entirely subcutaneous ICD System

The entirely subcutaneous implantable cardioverter defibrillator (S-ICD(®)) is emerging as a widely accepted therapeutic alternative to a conventional implantable cardioverter defibrillator (ICD) for prevention of sudden cardiac death. Essentially, the S-ICD(®) is promising in terms of reduction of electrode-related complications such as lead failure and infections. The conventional transvenous ICD has proven efficacy in various randomized clinical trials. The first results of S-ICD(®) studies confirm efficacy and safety in primary and secondary prevention as well. Owing to basic differences between S-ICD(®) and transvenous ICD—such as limited programming options and lack of pacing—not all patients are eligible for the S-ICD(®). Concerns exist regarding inappropriate shocks due to T-wave oversensing, dimensions of the device, and shorter battery longevity. However, the S-ICD(®) should be considered a useful supplementation of ICD therapy in those patients at risk for sudden cardiac death who are not expected to require pacing due to bradycardia or antitachycardic pacing.