system
A chat on subreddit /r/NoStupidQuestions
human
Well CPR doesn't *cure* anybody, what it does is buy time until defibrillation. It preserves brain function by moving oxygen. When someone receives 30 seconds of CPR then gets defibrillated quickly, as happens every day in every major hospital, they often survive. But when someone receives 20 minutes of CPR while waiting on an ambulance with a defibrillator, they rarely survive.

Publicly accessible AEDs are where it's at. Personally I think that everybody with a driver's license should have to pass a CPR &amp; AED class, and that AEDs should be available at basically every traffic light.
gpt
An AED doesn't help if your heart stops.
It's for abnormal rhythm.