Acute coronary syndromes

Primary diagnostic finding

Management

STEMI

ST-segment elevation in ≥2 contiguous ECG leads

Emergency reperfusion (eg, PCI)

Non-STEMI*

Serum troponin elevation

Medical management initially, revascularization within 24-48 hr

Unstable angina**

Consistent history (eg, rest angina)

*ECG shows ischemic (eg, ST-segment depression) or nonspecific changes but no ST-segment elevation.

**ECG is unremarkable or shows nonspecific changes & standard-sensitivity troponin is not elevated.  The use of high-sensitivity troponin testing renders unstable angina largely obsolete as a diagnosis.

PCI = percutaneous coronary intervention; STEMI = ST-segment elevation myocardial infarction.