Acute myocardial infarction (heart attack) requires immediate medical attention. Symptoms may include tightness or pressure in your chest, back, and jaw, shortness of breath, and sweating, among others, Acute myocardial infarction, also known as a heart attack, occurs when blood flow to the heart muscle is abruptly cut off, causing tissue damage, This is usually the result of a blockage in one or more of the coronary arteries. A blockage can develop due to a buildup of plaque, a substance mostly made of fat, cholesterol, and cellular waste products or due to a sudden blood clot that forms on the blockage