No. Many heart attacks cause arrhythmia, and that kills you. That’s why defibrillators are so important. Ascending dissections can linger, just like heart attack patients.
I have seen news about millions of heart attack victims make it to a hospital and still be alive. Yes, a minority of heart attack victims die very quickly as happened to my brother.
Break in the main Aorta? Very rare to make it to hospital surgery in time. Once the blood pressure has dropped dangerously low, the brain dies quickly from lack of oxygen circulating to the brain.