This document summarizes information about myocardial infarction (MI), also known as a heart attack. It discusses the causes of MI as being due to blockage of the coronary arteries, usually from atherosclerosis. It describes the symptoms of MI and risk factors such as age, sex, genetics, hypertension, high cholesterol, diabetes, and smoking. Treatment options for MI mentioned include coronary artery bypass graft surgery, percutaneous coronary intervention such as angioplasty and stenting, and fibrinolysis to break up blood clots in the heart.