Volunteer non-medical responders (e.g., office staff, bank tellers, merchants, and neighborhood volunteers) in both the intervention and control groups will be trained to provide the optimal standard of care: (a) recognize out-of-hospital cardiac arrest; (b) access 911 or its equivalent; and, (c) administer CPR. Volunteers in the intervention group will also be taught to use an AED promptly while awaiting arrival of the first public safety emergency medical team. The criteria for number and location of trained volunteers and devices will be a maximum 3-minute "walk through" to have the AED at the patient's side.