Difference between CAD and ACS

Acute Coronary Syndrome 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).

Patients who have symptoms of acute myocardial ischemia and are given an electrocardiogram (ECG or EKG) may or may not have an ST elevation.* (An ECG provides a graph of the heartbeat.* Portions of the graph are labeled P, Q, R, S and T.* An ST elevation describes a rise in a particular portion of this graph.)* Most patients who have ST-segment elevation will ultimately develop a Q-wave acute myocardial infarction (heart attack).* (The Q-wave describes another part of an ECG graph.)* Patients who have ischemic discomfort without an ST-segment elevation are having either unstable angina, or a non-ST-segment elevation myocardial infarction that usually leads to a non-Q-wave myocardial infarction.

Acute coronary syndrome thus covers the spectrum of clinical conditions ranging from unstable angina to non-Q-wave myocardial infarction and Q-wave 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.