Myocardial infarction (MI) or acute myocardial infarction (AMI), commonly known as a heart attack, results from the partial interruption of blood supply to a part of the heart muscle, causing the heart cells to be damaged or die. This is most commonly due to occlusion (blockage) of a coronary artery following the rupture of a vulnerable atherosclerotic plaque, which is an unstable collection of cholesterol and fatty acids and white blood cells in the wall of an artery. The resulting ischemia (restriction in blood supply) and ensuing oxygen shortage, if left untreated for a sufficient period of time, can cause damage or death (infarction) of heart muscle tissue (myocardium).
Typical symptoms of acute myocardial infarction include sudden retrosternal chest pain (typically radiating to the left arm or left side of the neck), shortness of breath, nausea, vomiting, palpitations, sweating, and anxiety (often described as a sense of impending doom). Women may experience fewer typical symptoms than men, most commonly shortness of breath, weakness, a feeling of indigestion, and fatigue. A sizeable proportion of myocardial infarctions (22–64%) are "silent", that is without chest pain or other symptoms. Source: Wikipedia