VF requires immediate defibrillation (200-400 J). If unsuccessful, initiate cardiopulmonary resuscitation (CPR) and standard resuscitative measures (Chap. 10. Cardiovascular Collapse and Sudden Death). Ventricular arrhythmias that appear several days or weeks following MI often reflect pump failure and may warrant invasive electrophysiologic study and implantation of a cardioverter defibrillator (ICD).