The PulsePoint mobile app alerts CPR-trained bystanders to someone nearby having a sudden cardiac arrest that may require CPR. The app is activated by the local public safety communications center simultaneous with the dispatch of local fire and EMS resources. The purpose of the app is to increase the survival rates of cardiac arrest victims by: Reducing collapse-to-CPR times by increasing citizen awareness of cardiac events beyond a traditional “witnessed” area, and reducing collapse-to-defibrillation times by increasing awareness of public access defibrillator (AED) locations through real-time mapping of nearby devices.