1. Section A: Introduction
Current nomenclature of ACS
Content Points:
The term “acute coronary syndromes” (ACS) refers to a constellation of clinical symptoms associated with acute myocardial ischemia.1
Patients may present with or without ST-segment elevation on the electrocardiogram (ECG). Unstable angina (UA) and non–ST-segment elevation myocardial infarction (NSTEMI) are considered to be closely related conditions, with pathogenesis and clinical presentation that are similar but differ in severity.
– The presence of markers of cardiac necrosis, such as the I- and T-subunits of the troponin complex (TnI, TnT) or the MB isoenzyme of creatine kinase (CK-MB), establishes a diagnosis of NSTEMI
– If no biochemical markers are present, the patient is diagnosed as having UA
Most patients with NSTEMI do not develop Q waves and are subsequently diagnosed as having non–Q-wave MI (NQMI).
Most patients with ST-segment elevation MI (STEMI) develop Q waves and are diagnosed as having a Q-wave MI (QwMI).

2. ACS: Common presentation of CAD
Content Points:
UA and MI are major causes of emergency medical care and hospitalization.
UA and NSTEMI accounted for 1,433,000 hospitalizations in 1996, according to data from the National Hospital Discharge Survey.2
In 1997, there were over 5 million emergency room visits for evaluation of chest pain and related symptoms.3
Importantly, women appear to be at comparable risk for ACS as men.
– In 1996, 46% of patients admitted for UA were women