EPIDEMIOLOGY The leading cause of death in the United States is coronary heart disease. An estimated 15.4 million Americans suffer from coronary heart disease, making them seven times more at risk of having a heart attack than the general population(1). It is estimated that the annual incidence of myocardial infarction is equal to 715,000, of which approximately 29% is represented by an ST-segment elevation myocardial infarction (STEMI) (1). It is important to note that the death rate from STEMI has decreased over the years; however, there is still a considerable proportion of eligible STEMI patients who do not receive any form of reperfusion therapy. In an analysis of 10,954 STEMI patients enrolled in the Global Acute Coronary Events Registry, 33% of eligible patients did not receive reperfusion therapy(2).PATHOPHYSIOLOGYUnder normal conditions, the coronary arteries supply oxygenated blood to the myocardium for meet the oxygen demands of the heart muscle supplied by those arteries. In patients with coronary atherosclerosis, an atherosclerotic plaque develops in the lumen of the coronary artery. When this plaque becomes vulnerable, its fibrous cap can rupture and stimulate platelet aggregation and thrombus formation (3). An occlusive thrombus forms which prevents blood flow through the coronary artery, thus leading to ischemia of the myocardium supplied by that artery. Evidence of this ischemia is reflected on the electrocardiogram as ST-segment elevation. Due to lack of blood flow and oxygen supply, cardiac myocytes begin to die in a wave-like manner, from the endocardium to the epicardium, over several hours (3). Restoration of blood flow through the occluded coronary artery must occur quickly to prevent the formation of a large infarct. CLINICAL PRESENATION The most typical presentation of acute myocardial infarction is chest pain. It is often described as a squeezing or squeezing sensation in the middle of the chest. Unlike angina, chest pain due to myocardial infarction continues at rest and is generally not relieved by nitroglycerin(4). The pain will often radiate to the shoulder, arm, neck, jaw, or back. However, some patients who have had a heart attack may present without any chest pain. A retrospective secondary analysis of 2,541 patients presenting with ischemic heart disease found that women (P=.007), diabetics (P=.01), and older patients (P=.0001) were less likely to present with classic pain thoracic(5) . They may experience some of the associated symptoms including nausea and vomiting, cold sweats, dizziness, shortness of breath, or feeling weak or apprehensive(4). Physical examination findings for patients with acute myocardial infarction vary significantly.