The chances of survival after a myocardial infarction depend on a number of factors. The survival rates can vary from 96% to only 30 to 40%. The favourable factors include a young patient, who recieves early treatment like streptokinase and aspirin, a small infarction, without any complications, early resolution of chest pain and no past history of a heart attack.
The factors predicting a high mortality are: late presentation to a doctor, big infarction, complications like heart failure presenting as severe shortness of breath, very low blood pressure which remains low despite administration of effective drugs, history of previous heart attacks and advanced age.