New (2014) Guidelines for Managing Patients with Non–ST-Elevation Acute Coronary Syndromes

The American Heart Association (AHA) and the American College of Cardiology (ACC) have just issued (September 23, 2014) new guidelines for the management of patients with non-ST elevation (NSTE) acute coronary syndromes (ACS).1 They start with definitions. Absence of persistent ST elevation defines NSTE-ACS (except in patients with true posterior myocardial infarction –MI). Further classification of NSTE-ACS is based on whether cardiac troponin is elevated (NSTEMI) or not (unstable angina - UA). ST depression, transient ST elevation, and/or T-wave inversion may be present but are not required for a diagnosis of NSTEMI. Abnormalities on the electrocardiogram (ECG) and elevated cardiac troponins in isolation are insufficient to make the diagnosis of ACS but must be interpreted in the appropriate clinical context.1,2 Thus, UA and NSTEMI differ primarily by whether ischemia causes myocardial damage with a detectable cardiac biomarker. With the increasing sensitivity of cardiac troponin assays, biomarker-negative ACS (UA) is becoming rarer... (excerpt