Powell BD, Saxon LA, Boehmer JP, Day JD, Gilliam FR, Heidenreich PA, Jones PW, Rousseau MJ, Hayes DL. Survival after shock therapy in implantable cardioverter-defibrillator and cardiac resynchronization therapy-defibrillator recipients according to rhythm shocked. The ALTITUDE survival by rhythm study. J Am Coll Cardiol. 2013 Oct 29; 62(18):1674-1679.