Discrimination between QRS and T Waves Using a Right Parasternal Lead for S‐ICD in a Patient with a Single Ventricle

The subcutaneous implantable cardioverter‐defibrillator (S‐ICD) is a useful option for patients with a single ventricle (SV) in which transvenous leads are contraindicated because of intracardiac shunts. We report a case in which a right parasternal lead placement was indicated for an S‐ICD in a resuscitated patient with an SV. There were significant changes in the magnitude of R to T waves ratio in the right compared to the left parasternal lead position. Screening in the right parasternal position is effective for selecting appropriate patients with congenital heart disease for S‐ICD implantations.