ST Elevation in aVR: An Atypical Presentation of Pulmonary Embolism.

ST elevation in aVR on the electrocardiogram (ECG) indicates high-risk acute coronary syndrome (ACS) but is rarely reported in pulmonary embolisms (PEs). We present a 47-year-old female with a history of PE and ankylosing spondylitis admitted for chest pain, nausea, and an episode of possible collapse. Her ECG showed ST elevation in aVR with anterolateral ST depressions, prompting a normal emergency coronary angiogram. Bedside echocardiography revealed right ventricular (RV) dilatation, and lab tests showed elevated D-dimer levels and troponin. Urgent computed tomography of the pulmonary arteries (CTPA) confirmed large bilateral PEs. The patient was treated with Enoxaparin and transitioned to Warfarin, resulting in symptom improvement. ST-segment elevation in lead aVR may mimic ACS but suggests significant conditions like PE, often from RV strain and impaired coronary blood flow due to acute RV failure. Clinicians should suspect PE in patients with aVR changes, especially with relevant clinical history and signs of RV pressure overload on echocardiography, to prevent misdiagnosis and ensure timely care.