Subcutaneous or Transvenous Defibrillator Therapy

Background:The subcutaneous implantable cardioverter-defibrillator(ICD)was designed to avoid complications related to the transvenous ICD lead by using an entirely extrathoracic placement.Evidence comparing these systems has been based primarily on observational studies.Methods:We conducted a noninferiority trial in which patients with an indication for an ICD but no indication for pacing were assigned to receive a subcutaneous ICD or transvenous ICD.The primary end point was the composite of device-related complications and inappropriate shocks;the noninferiority margin for the upper boundary of the 95%confidence interval for the hazard ratio(subcutaneous ICD vs.transvenous ICD)was 1.45.A superiority analysis was prespecified if noninferiority was established.