Ramsey County officials on Thursday unveiled a smartphone app that can direct people with basic medical training to help someone suffering a potentially fatal cardiac arrest — even before an ambulance can arrive.

The PulsePoint app is meant for people trained in cardiopulmonary resuscitation and for people who can use automatic external defibrillators. Another related app will direct bystanders to any nearby defibrillator. Both are free in Apple and Android app stores.

Fire and emergency medical officials from around the county unveiled the new program at a fire station in Roseville Thursday morning. In Minnesota, it's already been activated in St. Louis Park, Moorhead and Winona. It's also used by the La Crosse, Wis.-based Gundersen Tri-State Ambulance, said PulsePoint, the San Francisco-based nonprofit that runs the system.

"When seconds count, we need everyone's help to save lives," said David Brosnahan, Roseville's assistant fire chief.

Scott Williams, deputy Ramsey County manager, said there are already 1.3 million PulsePoint app subscribers around the country. The county pays about $13,000 a year to link its computer-aided-dispatch system that relays 911 calls through a dispatcher to the PulsePoint service.

Sudden cardiac arrest happens every day in St. Paul and its suburbs. County officials said they got about 400 calls reporting sudden cardiac arrest in Ramsey County last year.

Emergency communications manager Jonathan Rasch said there were about 60 calls that could have alerted people nearby to someone in need of help — the app only sends out alerts for emergencies in public places, not in private homes.

Rasch said the technology uses publicly available shipping address data to identify locations that aren't appropriate for an alert.

The software, he added, automatically sends out an audible alert, maps and descriptions to anyone within a quarter mile of someone in need of help, and who could likely reach someone in seconds, while trained medical personnel are still on their way.

The alerts are sent out within one-eighth of a mile in downtown St. Paul because it may be harder to reach someone in the urban core.

Quick action can literally be a matter of life and death, said Dr. Bjorn Peterson, assistant medical director for emergency medical services at Regions Hospital in St. Paul. He said more than 300,000 people a year in the U.S. suffer a sudden cardiac arrest every year.

"Unfortunately, the survival over decades has still remained only about 10 percent," Peterson said. "The survival is higher when the arrest happens in a public place and its even higher when the victim gets bystander CPR. The addition of bystander CPR to the chain of survival can increase the likelihood of survival by two or three times."

And with a phone in practically everyone's pocket, Ramsey County hopes to make that happen whenever possible.

Where to get the PulsePoint app

• iTunes store

• Google Play store for Android