NSTEMI
Also calledNon-ST-elevation myocardial infarction · Non-STEMI · Non-ST-segment elevation myocardial infarction
Definition
An acute myocardial infarction (a rise and/or fall of cardiac troponin with at least one value above the 99th-percentile upper reference limit, with evidence of acute ischemia) in a patient without ST-segment elevation at presentation. The ECG may be relatively normal or show ST depression, transient ST elevation or new T-wave inversion; none of these is required for the diagnosis. It differs from unstable angina, which can share the symptoms and ECG findings but has troponin values that stay at or below the 99th percentile.
Sources
- Thygesen K, Alpert JS, Jaffe AS, et al. Fourth universal definition of myocardial infarction (2018). Circulation. 2018;138(20):e618-e651. doi.org/10.1161/CIR.0000000000000617
- Amsterdam EA, Wenger NK, Brindis RG, et al. 2014 AHA/ACC guideline for the management of patients with non-ST-elevation acute coronary syndromes. Circulation. 2014;130(25):e344-e426. doi.org/10.1161/CIR.0000000000000134
Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.