Evaluation of Subcutaneous Implantable Cardioverter Defibrillator Performance in Patients with Ion Channelopathies from the EFFORTLESS Cohort and Comparison with a Meta-analysis of Transvenous ICD Outcomes

Abstract Background The subcutaneous ICD (S-ICD) is an alternative to conventional transvenous ICD (TV-ICD) therapy to reduce lead complications. Objective To evaluate outcomes in channelopathy versus patients with structural heart disease in the EFFORTLESS-SICD Registry and with a previously reported TV-ICD meta-analysis in channnelopathies. Methods The EFFORTLESS registry includes 199 patients with channelopathies (Brugada Syndrome 83, Long QT Syndrome 24, Idiopathic Ventricular Fibrillation 78, others 14; and 786 patients with structural heart disease. Results Channelopathy patients were younger (39±14 versus 51±17 years; P 200 BPM (P=.0002). Annualized appropriate shock, IAS, and complication rates appear to be lower for the S-ICD versus meta-analysis TV-ICD patients, particularly lead complications. Conclusion EFFORTLESS demonstrates similar S-ICD efficacy and a non-significant, lower rate of inappropriate shocks in channelopathy patients as compared to structural heart disease. Comparable IAS rates were achieved with the device to programmed to higher rates for channelopathy patients.