Figure 3 12-lead ECG strips at 25 mm/sec before (A ) and after (B ) biventricular pacemaker (CRT-P) implantation with His-Optimized Cardiac Resynchronization Therapy in a subcutaneous implantable cardioverter-defibrillator (s-ICD) patient. Paced QRS complexes were smaller (100 msec) than spontaneous ones (115 msec). Vector ECG strips (Primary, Secondary and Alternative) from the Automated Screening Tool for s-ICD (Boston Scientific) are shown in both the supine (C ) and upright (D ) positions, with correct paced QRS identification in both cases.