The purpose of the study is to compare, three months after implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D), the apnea-hypopnea index (AHI) obtained from conventional in-lab NPSG/NPG (AHIPSG) with similar indices obtained from autoscoring algorithms of the ApneaScan™, an implantable impedance-based respiration sensor (AHIAS).