How high can blood pressure get before a heart attack occurs?

BP varies...: Varies. It can be very high due to pain and a feeling of dread. It can be low if the heart is weak due to a large heart attack.

Depends: This is very individual. If you have had high blood pressure for a long time, your body is used to it and may tolerate it longer. If you for example take Cocaine or other drugs that raise your blood pressure suddenly, even a small increase can give you a heart attack. No guarantees either way..