BACKGROUND: Approximately one-quarter to one-third of patients with non-ST-elevation myocardial infarction have a completely occluded culprit coronary artery but are not routinely referred for emergent reperfusion. A growing literature describes electrocardiographic patterns purported to identify acute coronary occlusion (ACO) in non-STEMI populations, but guideline adoption has been limited and inconsistent. We conducted a scoping review to map the extent, characteristics, and methodologies of primary studies examining non-ST-elevation ECG patterns against reference standards for ACO. METHODS: Electronic databases were searched and supplemented by backward and forward citation tracking. Primary studies were included evaluating non-ST-elevation ECG patterns against an angiographic or composite reference standard for ACO. Studies using stenosis severity or anatomical disease burden as the reference standard were excluded. RESULTS: Forty-two studies were included, yielding 78 pattern-level data sources spanning 20 ECG patterns. Only 23/78 data sources evaluated undifferentiated ACS patients. Measurable index test definitions were present in 33/78 data sources. Reference standards were highly heterogeneous. Although 70/78 data sources defined a reference standard for ACO, only 29/78 reported diagnostic test accuracy values, most of which were in the LBBB/VPR category. CONCLUSIONS: The literature is heterogeneous, methodologically uneven, and concentrated in a small number of pattern categories. Outside the LBBB/VPR criteria, diagnostic test accuracy data in NSTE-ACS populations are sparse, and methodological features that critically affect their interpretation are inconsistently reported. These findings identify substantial gaps in the primary literature and inform the scope of future pattern-specific diagnostic test accuracy systematic reviews.