What dosage of aspirin for suspected heart attack?

Call 911 then 325 mg: For someone with new-onset of symptoms suggesting a heart attack, call 911 then chew and swallow a 325 mg Aspirin tablet. For someone who has had a heart attack in the past, daily Aspirin 81-162mg is recommended. This is termed secondary prevention.

Aspirin: A 325mg Aspirin tablet is appropriate if not already taking aspirin.