This was a study of a comprehensive, integrated community approach in which volunteer non-medical responders (lay volunteers without a traditional responsibility to take charge in medical emergencies as their primary job description) were trained to use automated external defibrillators (AEDs). This approach is called Public Access Defibrillation (PAD). The hypothesis investigated was that PAD would significantly increase survival in out-of-hospital cardiac arrest by reducing the time interval from collapse to defibrillation. The specific aim of this randomized, controlled trial was to measure survival to hospital discharge following out-of-hospital cardiac arrest in community units trained and equipped to provide public access defibrillation in addition to optimal standard care, compared to community units trained to provide optimal standard care (recognition of out-of-hospital cardiac arrest, 911 access, cardiopulmonary resuscitation). Secondary aims included the comparison using Utstein criteria (Annals of Emergency Medicine 1991;20:861-74), neurological status, quality of life, cost, and cost-effectiveness between the two groups.