Surviving a heart attack without medical treatment is sometimes possible but you shouldn't chance it.
When you think you're having a heart attack put an aspirin under your tongue and allow it to dissolve and then call 911 to get help.
Even if you think it's not too severe you should still call 911 just to be safe.
It's better to get the ambulance or first responding medical professionals to your aid and then find out it wasn't too severe than not have them get to you in time and then you die.
Heart Attacks can be very serious so you should always seek medical attention if you think you're having a heart attack.