RIGHT will compare the incidence of Ventricular Tachycardia/Fibrillation (VT/VF) therapies delivered for Supraventricular Tachycardia (SVT) episodes using VITALITY 2 devices with Rhythm ID™ to that of ICDs employing other rhythm discrimination algorithms. Appropriateness of therapies will be assessed after independent adjudication of all VT/VF events leading to therapy. Comparisons will be made between device manufacturers across patient populations receiving either a dual- or single-chamber device.