Screening of vectors prior to subcutaneous implantable cardioverter-defibrillator placement. The subcutaneous implantable cardioverter-defibrillator consists of a generator implanted in the left lateral chest wall and a lead placed superficially to the sternum. There are three possible vectors to detect electrograms—two involving the generator (primary, secondary) and one involving only the lead (alternate). Prior to implantation, screening takes place to ensure these vectors will be suitable for analysis based on QRS and T wave size, stability of QRS complex morphology during postural change. In this gentleman, the secondary vector failed automated screening.