CPR•September 8, 2026

What To Do When Someone Goes Into Cardiac Arrest

A clear overview of recognizing cardiac arrest, calling for help, beginning CPR, and using an AED.

Training participants learning about CPR

Important: This article provides general educational information and does not replace hands-on training, emergency services, medical care, or mental health treatment. In an emergency, call 911 or your local emergency number.

Cardiac arrest is an emergency. If a person is unresponsive and not breathing normally—or is only gasping—act immediately.

Call, compress, and use an AED

Call 911 or your local emergency number and put the phone on speaker. Send someone to retrieve an AED if one is available.

Begin CPR and follow the dispatcher’s instructions. Push hard and fast in the center of the chest. Use the AED as soon as it arrives and follow its spoken prompts.

Check that the scene is safe.
Tap and shout to check responsiveness.
Call emergency services and get an AED.
Start CPR; continue until help takes over or the person shows clear signs of life.