Acute coronary-occlusion myocardial infarctions: performance of the STEMI criteria and evolving alternative approaches.

Acute coronary syndrome (ACS) includes ST elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (NSTEMI) and unstable angina (UA), which occur predominantly due to atherothrombosis with varying degrees of acute occlusion of coronary vasculature. Coronary angiogram and subsequent percutaneous coronary intervention (PCI) are central to management of acute coronary occlusions; however, the timing of coronary angiogram varies significantly across these pathologies based on current guidelines. The STEMI criteria are electrocardiographic features utilized to rapidly triage patients to catheterization laboratories, because these criteria are felt to be specific for acute coronary occlusion of culprit coronary vessels. Patients who do not fulfill STEMI criteria are triaged as NSTEMIs with delayed coronary reperfusion strategies. A significant proportion of patients with NSTEMI ACS are found to have acute coronary occlusion (ACO) of coronary vessels. Some NSTEMI patterns on electrocardiogram that are considered specific for acute coronary occlusion myocardial infarction (ACOMI) have been aptly labeled "STEMI-equivalents" and are thus recognized as high-risk features in expert statements but, as of yet, not formally adopted in guidelines. Here, we review the current literature on ACOMI in NSTEMI ACS and the "STEMI Equivalents". We discuss the potential role for additional studies, revised diagnostic criteria, and predictive tools to better stratify patients with NSTEMI ACS for urgent versus delayed reperfusion.