Tucson residents are now just a smartphone application away from receiving trained assistance from a bystander if they suffer a cardiac emergency in a public location.

The Tucson Fire Department announced Wednesday its participation in the PulsePoint community, which connects citizens with CPR-trained members of the public and information about nearby automated external defibrillators.

The smartphone app allows Tucson residents who are trained in CPR and the use of AEDs, and who have indicated their willingness to respond to an emergency to get an alert on their smartphones if someone near them is having a heart attack or sudden cardiac arrest .

Public safety agencies have to partner with PulsePoint because the alerts are sent based on calls to the departments’ dispatchers. However, anyone who has CPR training can download the phone app and receive the alerts.

When a call for help is received by public safety dispatcher, the 911 system notifies PulsePoint, which alerts nearby trained bystanders, generally within walking distance of the patient, with a map and GPS directions to the victim, and the location of the nearest AED.

In many cases, the victim can receive help from trained bystanders before paramedics arrive. The alert does not give personal details of the person having the cardiac emergency.

Rural/Metro Fire Department personnel have been using PulsePoint, and nine other departments have recently signed on, ensuring that 95 percent of the greater Tucson area is covered, said Assistant Tucson Fire Chief Joe Gulotta.

In addition, roughly 1,000 Pima County sheriff’s deputies and corrections officers will download the app and will be available to help in a CPR emergency, even when they’re off duty.

In February 2014, Michael Chaison collapsed from a heart attack on a Salpointe Catholic High School athletic field.

Within minutes, bystanders administered CPR and used an external defibrilator to shock his heart, before paramedics arrived and transported him to a hospital.

Chaison said he was clinically dead on the field, but the quick action of the people around him saved his life.

Over the past several years, the nonprofit Steven M. Gootter Foundation has donated more than 200 AEDs to Tucson-area schools and agencies — including the defibrillator that was used on Chaison at Salpointe.

Roughly 1,000 people nationwide die every day from sudden cardiac arrest, and citizens being notified of a nearby emergency will be of great help, officials say.

“Time counts, and the first 10 minutes (after a cardiac event) is critical time,” said foundation president Andrew Messing. “There will be lives that can be saved with this app.”

Contact reporter Caitlin Schmidt at cschmidt@tucson.com or 573-4191. On Twitter: @caitlincschmidt