An acute myocardial infarction, also called a heart attack, happens when a blood vessel in the heart suddenly becomes blocked. Blood vessels carry blood and oxygen. When a blood vessel in the heart gets blocked, blood cannot get to part of the heart. This part of the heart does not get enough oxygen. This is called ischemia. When the heart muscle becomes ischemic (does not get enough blood and oxygen), the ischemia often causes chest pain. This is called Angina Pectoris. If the ischemia lasts long enough, the heart muscle that is not getting enough oxygen dies. This is called an infarction. "Myocardial infarction" means "infarction (muscle death) in the heart muscle."