CPR (Cardiopulmonary Resuscitation) is a two-step chest compression, rescue breath procedure delivered to a victim in cardiac arrest. The heart ceases pumping blood in cardiac arrest, and the victim (now in Ventricular Fibrillation, or VF) requires CPR and a heart shock known as Defibrillation. Administering CPR can buy time by supplying the brain and heart with small quantities of blood until regular heart function is resurrected.