Chest Pain and ST-Segment Elevation in Lead aVR

EMS is dispatched to a 63 year old male complaining of chest pain.

On arrival you find the patient lying supine in bed, alert and oriented to person, place, time and event. His general appearance is poor. He is pale, but not diaphoretic. Skin temp is normal. His chest pain is substernal 6/10 and non-radiating.

Vital signs

  • RR: 12 non-labored
  • HR: 68
  • NIBP: 97/55
  • SpO2: 81% on room air

Breath sounds are clear bilaterally.

Past medical history

  • 4-vessel bypass approximately 6 years ago
  • End stage renal disease
  • Diabetes

The cardiac monitor is attached.

A 12 lead ECG is obtained.

How sick is this patient?

What do you think is going on?


This was the first case I ever posted that showed ST-segment elevation in leads aVR and V1 with widespread ST-segment depression.

A recent Twitter poll showed that 72% of the #FOAMed community considered this finding to be a STEMI equivalent (indicating left main coronary artery occlusion) complete with prehospital activation of the cardiac cath lab.

It is probably based on this article.

Rokos I, French W, Mattu A et al. Appropriate Cardiac Cath Lab activation: Optimizing electrocardiogram interpretation and clinical decision-making for acute ST-elevation myocardial infarction. American Heart Journal. 2010;160(6):995-1003.e8. doi:10.1016/j.ahj.2010.08.011.

However, this is controversial (even though I suggested the same thing here).

Stephen Smith, M.D. (@SmithECGBlog) argues that ST-segment elevation in leads aVR and V1 with widespread ST-segment depression really represents subendocardial ischemia, which may represent left main coronary occlusion or proximal LAD occlusion, but it may also represent left main insufficiency, 3 vessel disease, demand ischemia, anemia, CO poisoning, aortic stenosis, or some other cause that requires further workup in the Emergency Department.

The bottom line

Make sure you have buy-in from Emergency Medicine and Cardiology before you start calling this from the field!

Further reading

Five primary patterns of ischemic ST-depression, with ST-elevation. Some are STEMI equivalents.

The difference between left main occlusion and left main insufficiency

ST-segment elevation in lead aVR. Is this a STEMI equivalent?

The 12-Leads of Christmas: aVR


  • Nicole says:

    It still presents as a time sensitive cardiac event yes? It says “may” be a STEMI, since we dont have the further diagnostics in the truck I feel I will still call it in the same, the hospital will activate the cath lab should they deem fit.

  • Jack says:

    Hello Tom,

    Thanks for the post! Very interesting case!

    Any chance you could find out what’s the verdict from the cathlab / emerge?


    • Micah S. says:

      I’m curious about that too. I’m especially curious to know the result of his labs, and especially his lytes. In end-stage renal patients with funky ECG’s, severe electrolyte imbalance always moves up in my list of suspicions.

  • Kenny says:

    Assuming his 81% O2 sat is abnormal I would attempt to correct that first then re take the 12 lead after a few minutes of good oxygenation and see if any depression corrects or improves. Treat pt under ACS protocol and transmit 12 lead to ER for further analysis PTA to ED.

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