Survival from cardiac arrest doubled when bystanders stepped in to use a publicly-available automated external defibrillator rather than wait until emergency responders arrived. The study showed that the longer it takes emergency personnel to arrive, the greater the benefit of a bystander using an AED to shock the victim. Victims who received a defibrillator shock from a bystander had far greater chances at survival and being discharged from the hospital than those who did not.