Primary myocardial infarction arises spontaneously from acute coronary pathology, such as coronary thrombus or dissection. Secondary myocardial infarction refers to coronary pathology exposed by supply-demand mismatch by some secondary cause. An acute myocardial infarction is a heart attack. Learn about the symptoms, causes, diagnosis, and treatment of this life threatening condition. Acute myocardial infarction is myocardial necrosis, usually resulting from acute obstruction of a coronary artery. Symptoms include chest discomfort with or without dyspnea, nausea, and/or diaphoresis. Diagnosis is by electrocardiography (ECG) and a significant elevation in cardiac troponin. Our understanding of the causes, diagnosis, and treatment of acute myocardial infarction (AMI) has evolved significantly over the last 40 years. In the early 20th century, AMI was generally considered a fatal event diagnosed only at autopsy. What is a heart attack? A heart attack occurs when one of the heart's coronary arteries is blocked suddenly or has extremely slow blood flow. A heart attack also is called a myocardial infarction. The usual cause of sudden blockage in a coronary artery is the formation of a blood clot (thrombus). Myocardial infarction (MI), commonly known as a heart attack, remains a leading cause of morbidity and mortality worldwide. It arises from a sudden cessation of coronary blood flow, most often due to plaque rupture and subsequent thrombus formation. An acute complete blockage of a medium or large heart artery usually means you've had an ST elevation myocardial infarction (STEMI). A partial blockage often means you've had a non-ST elevation myocardial infarction (NSTEMI). What is acute myocardial infarction? Myocardial infarction (MI) is one of the most severe presentations of coronary heart disease (CHD). 1 An acute myocardial infarction is caused by necrosis of myocardial tissue due to ischaemia, usually due to blockage of a coronary artery by a thrombus. A heart attack (myocardial infarction) is a sudden drop in blood flow to your heart muscle. It’s usually due to a blockage in one of the arteries that supply blood to your heart (coronary arteries). What is a heart attack, also called a myocardial infarction? Find information and resources on what happens during a heart attack, surviving a heart attack, symptoms and treatments.