Acute coronary syndromes (ACS) encompass clinical symptoms compatible with acute myocardial ischemia/injury. Typically, these include ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), and unstable angina (UA).
ACS is categorized as STEMI when symptoms of myocardial ischemia are associated with persistent electrocardiographic (ECG) ST elevation and subsequent release of biomarkers of myocardial necrosis. In the absence of left ventricular (LV) hypertrophy or left bundle-branch block (LBBB), ST elevation diagnosis is determined by new ST elevation at the J point in at least 2 contiguous leads of 2 mm (0.2 mV) in men or 1.5 mm (0.15 mV) in women in leads V2–V3 and/or of 1 mm (0.1 mV) in other contiguous chest leads or the limb leads. Most STEMI patients will also have ECG evidence of Q-wave infarction. New or presumably new LBBB is considered a STEMI equivalent.
ACS is categorized as NSTEMI in the absence of persistent ST-elevation, except in patients with true posterior myocardial infarction (MI). NSTEMI is further subdivided on the basis of cardiac biomarkers of necrosis. If cardiac biomarkers are elevated and the clinical context is appropriate, the patient is considered to have NSTEMI, otherwise a diagnosis of UA is made.
ACS typically represents a medical emergency, and outcomes are closely linked with the speed with which patients obtain appropriate care. The following notes provide physicians with a guide to the management of ACS, based on currently available treatment guidelines. The goal of this program is to assist physicians in rapidly making treatment decisions at crucial points during the management of patients with ACS.
Eddy Lang, MDCM- CCFP(EM)-CSPQ
Michel Le May, BSc, MD
Mark Mensour, MD CCFP EM ANAES FCFP