CHARLOTTE, N.C. -- Would you know what to do if you witnessed a heart attack? There’s an app for that. 

Mecklenburg County MEDIC is rolling out a partnership with a free app, "Pulsepoint," starting this week. 

Users receive notifications whenever CPR is needed within a mile of their location.

Experts say bystanders keep CPR going on cardiac arrest patients until help arrives.

“Brain death begins five minutes after the heart stops," cardiologist Dr.Gary Niess said. "So, if MEDIC gets there in five to 10 minutes, they may be able to bring the patient back, but they may be significantly damaged by brain damage.”

Sudden cardiac arrest survivor Johnnie Davis says his wife saved his life by doing CPR. 

“You can learn how to do CPR in five minutes or less and have that knowledge to know that you can save somebody’s life, should you be in that situation.” 

The app also has a CPR guide that takes you step-by-step through what to do.

Find out more at http://www.pulsepoint.org​  and https://www.keepthebeatmeck.com.