Occlusive Myocardial Infarction: A Practical Review of STEMI-Negative Coronary Occlusion in Acute Coronary Syndromes

ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) remain the dominant operational categories for acute coronary syndrome triage because they are simple, widely implemented, and closely linked to reperfusion pathways. However, diagnostic ST-segment elevation and acute coronary occlusion are not synonymous. A clinically important subgroup of patients classified as NSTEMI have total or near-total culprit-artery occlusion and may experience delayed angiography despite ongoing myocardial ischemia. This structured narrative review examines the rationale, evidence, electrocardiographic patterns, quantitative bedside criteria, and emerging technologies relevant to occlusion myocardial infarction (OMI), with particular emphasis on STEMI-negative coronary occlusion. Conventional STEMI criteria are highly specific but incompletely sensitive for acute coronary occlusion, particularly in posterior or circumflex infarction, early anterior occlusion, left bundle branch block, ventricular paced rhythm, and transient reperfusion. Recognition of OMI therefore requires integration of ECG morphology, reciprocal changes, serial ECG evolution, clinical presentation, troponin kinetics, and adjunctive imaging rather than reliance on ST-segment thresholds alone. Practical patterns include hyperacute T waves, the de Winter pattern, posterior OMI, modified Sgarbossa-positive conduction abnormalities, subtle anterior OMI, and selected high-risk ischemic patterns. Artificial intelligence may improve scalable detection of subtle occlusion patterns, although external validation, workflow integration, explainability, and prospective outcome studies remain necessary. Current evidence supports OMI as a promising complementary diagnostic framework rather than an established replacement for guideline-based STEMI/NSTEMI classification. Prospective implementation studies are required to determine whether OMI-guided pathways improve clinical outcomes without unacceptable false-positive catheterization-laboratory activation.