Electrocardiogram Diagnosis: ST-Depression With T Wave Inversion in Lead Augmented Vector Left as Harbinger of Inferior ST-Elevation Myocardial Infarction

A 53-year-old male presented to the emergency department (ED) after waking up with retrosternal chest discomfort. An initial prehospital 12-lead electrocardiogram (ECG) obtained by emergency medical services indicated sinus rhythm with ST-segment depression and T wave inversion in lead augmented vector left (aVL) but without significant ST-segment elevations. Upon ED arrival, a repeat ECG demonstrated minimal ST-segment elevation in the inferior leads, raising concern for an evolving inferior ST-segment elevation myocardial infarction (STEMI) and prompting cardiac catheterization laboratory activation. A repeat ECG obtained 18 minutes after the initial ED ECG confirmed acute inferior STEMI. Coronary angiography revealed 70% ulcerated stenosis in the mid right coronary artery (RCA) and 100% thrombotic occlusion of the distal RCA. Successful percutaneous coronary intervention to the occluded RCA was undertaken with restoration of Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow. The patient was discharged on hospital day 3. This case underscores the significance of reciprocal changes in lead aVL as an early marker of inferior STEMI, as well as the importance of serial ECGs and timely intervention to optimize patient outcomes in acute coronary syndrome.