Abstract Body (Do not enter title and authors here): Case Description:
Occlusion myocardial infarctions (OMI) can present with minimal ECG changes, making diagnosis challenging without high clinical suspicion. STEMI criteria have limited sensitivity for acute coronary occlusion (ACO), and patients with NSTEMI with ACO have longer time to angiography and worse outcomes compared to patients with STEMI and ACO. We present a 43-year-old male with BMI 36, hypertension, and a 30 pack-year smoking history presented with three days of intermittent chest pain radiating to the back with nausea and dyspnea. Symptoms progressed, prompting repeated visits to urgent care and ultimately to the emergency department (ED). On ED arrival, ECG was non-diagnostic. Troponin I was markedly elevated at 5,548 ng/L. Serial ECG revealed hyperacute T waves without conventionally diagnostic ST elevation and troponin rising to 25,763 ng/L. The patient underwent coronary angiography 13 hours after arrival, revealing acute thrombotic occlusion of the proximal right coronary artery. Percutaneous coronary internvention was performed with resolution of pain. Repeat ECG showed reperfusion changes, and echocardiogram showed inferior hypokinesis.

Discussion:
This case highlights the diagnostic challenge in patients with OMI without STEMI. Despite high-risk features, there was delayed recognition and intervention. This delay is consistent with empirical evidence that the highest risk NSTEMIs undergo urgent catheterization 6.4% of the time. The case also exemplifies how elevated and rising troponins, even without dramatic ECG changes, should prompt urgent management. Retrospective analysis using the Queen of Hearts artifical intelligence ECG model helped identify diagnostic ECG findings that were not recognized in real time. This tool proved valuable in highlighting findings consistent with inferoposterior OMI, reinforcing its potential role in supporting earlier recognition of high-risk ECG patterns. Early invasive evaluation should be considered in patients with ECGs that are diagnostic for OMI without satisfying STEMI criteria.