Aspirin can save your life when you have a heart attack and what you do is put the aspirin on your tongue and not swallow it.
When you swallow the aspirin it takes around 15 minutes for the aspirin to take effect and get into your blood stream but when you sit the aspirin on your tongue and let it dissolve it gets into your blood stream much faster.
The aspirin thins your blood which helps stop the heart attack from happening.
You should still call 911 though but do take the aspirin when you feel like you're having a heart attack.