aVR Rears its Ugly Elevation

A cardiologist's office calls 911 for an elderly patient who suffered a syncopal episode. The patient presented to the physician's office for a few weeks of bilateral arm pain and fatigue. The patient experienced mild dyspnea on exertion and was undergoing a chemical stress test when he experienced a brief syncopal episode. The patient was pain free at the time of EMS arrival. The patient was awake and alert. Vital signs:
BP: 104/70
P: 100
R: 22/non labored
Sp02: 96%

The cardiologist suggested transport to a facility capable of percutaneous coronary intervention. Why was the cardiologist so concerned (aside from the presence of an elderly patient with syncope in his office)? What's going on with this ECG?

12 lead ECG

12 Lead Interpretation and Discussion

The patient's rhythm is a borderline sinus tachycardia. ST segment elevation is present in leads aVR and V1. Diffuse ST segment elevation is present in the inferior and lateral leads. Though ST segment elevation in lead aVR isn't typically considered a "STEMI," there is sufficient evidence in the emergency cardiology literature that it should be considered as a "STEMI equivalent." ST segment elevation of > 1 mm (or > 0.5 mm in some studies) is associated with obstruction of the left main coronary artery. Furthermore, these patients are more likely to require surgical revascularization (CABG) or experience congestive heart failure. The skilled paramedic will easily recognize the widespread and diffuse ST segment abnormalities. This patient requires evaluation at a facility capable of percutaneous coronary intervention.

Final 12 lead ECG Interpretation

Sinus rhythm, ST segment elevation in leads aVR and V1. Probable acute obstruction of the left main coronary artery. Diffuse ST segment depression in the inferior (II, III, aVF), anterior (V4-V6), and lateral (I, aVL) leads.

Suggested Readings

• Rokos IC, French WJ, Mattu A et al. Appropriate cath lab activation: optimizing electrocardiogram interpretation and clinical decision making for acute ST elevation myocardial infarction. Am Heart Journ. Dec 2010;160(6):995-1003

• Barrabes JA, Figueras J, Moure C, et al. Prognostic value of lead aVR in patients with a first non ST segment elevation acute myocardial infarction. Circulation. 2003;108(81):814-819

• Williamson K, Mattu A, Plautz CU. Electrocardiographic applications of lead aVR. Am J Emerg Med. 2006;24:864-874