Introduction: Lead augmented vector right (aVR) has been historically underestimated in the evaluation of acute coronary syndromes in the emergency department and other clinical settings. ST-elevation in aVR has shown to be a predictive marker of critical stenosis of the left main coronary and is associated with increased 30 day mortality.
Case Report: We report an unusual case of acute ST-elevation myocardial infarction (STEMI) consistent with left main disease presenting with aVR ST-elevation in a patient with ischemic stroke. During percutaneous coronary intervention (PCI), the patient was found to have a total occlusion of the distal left main coronary artery (LMCA) which was collateralized from a large, dominant right coronary artery (RCA) which had no obstructive lesions. We hypothesize that the electrocardiography (ECG) are secondary to hypotension-related hypoperfusion of RCA collateral circulation supplying the anterior wall, in the setting of a chronically occluded LMCA. The patient succumbed to his disease eleven days after presentation.
Conclusion: Our purpose is to raise awareness of the high mortality associated with this ECG abnormality. Prompt recognition of isolated aVR ST changes would allow for identification of high risk patients leading to an early invasive approach with appropriate activation of the catheterization laboratory.

Keywords: Augmented vector right (aVR) lead, Collateral circulation, Left main coronary artery, ST-elevation myocardial infarction (STEMI)