Acute Coronary Syndrome (ACS) is an umbrella term used to cover any group of clinical symptoms compatible with acute myocardial ischemia. Acute myocardial ischemia is chest pain due to insufficient blood supply to the heart muscle that results from coronary artery disease (also called coronary heart disease). Acute coronary syndrome thus covers the spectrum of clinical conditions ranging from unstable angina to myocardial infarction. These life-threatening disorders are a major cause of emergency medical care and hospitalization in the United States. Coronary heart disease is the leading cause of death in the United States. Unstable angina and non-ST-segment elevation myocardial infarction are very common manifestations of this disease.
The cardinal sign of decreased blood flow to the heart is chest pain experienced as tightness around the chest and radiating to the left arm and the left angle of the jaw. Other symptoms include chest pain, pain in upper body, shortness of breath, cold sweat, nausea, and lightheadedness.