STEMI
Also calledST-elevation myocardial infarction · ST-segment elevation myocardial infarction
Definition
An acute myocardial infarction with diagnostic new ST elevation, which usually reflects acute coronary occlusion. The ECG criterion is new ST elevation at the J point in at least 2 contiguous leads meeting the sex-, age-, and lead-specific thresholds (at least 1 mm in most leads; in V2 to V3 at least 2 mm in men aged 40 or older, 2.5 mm in men under 40, and 1.5 mm in women). By convention the STEMI label is given to a patient with ischemic symptoms who develops these ST elevations; infarction itself is confirmed by a rise and/or fall of cardiac troponin with at least one value above the 99th percentile upper reference limit.
Clinical noteA new or presumed-new left bundle branch block is no longer considered, on its own, diagnostic of STEMI. In left bundle branch block, ST elevation of at least 1 mm concordant with the QRS complex (one of the Sgarbossa criteria) may indicate acute ischemia.
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
- O'Gara PT, Kushner FG, Ascheim DD, et al. 2013 ACCF/AHA guideline for the management of ST-elevation myocardial infarction. Circulation. 2013;127(4):e362-e425. doi.org/10.1161/CIR.0b013e3182742cf6
Last reviewed 2 October 2026. Every definition in the EKG Dictionary cites the guideline, consensus statement or original paper it comes from.