AVR is not a diagnostic lead. Or so I have been telling people for many years because that is what I was taught. Then the other day I was at a cardiology CME, where a cardiologist was showing us various strips and he showed one that had ST elevation in AVR and widespread ST depression in other leads. Both he and the other cardiologist were in agreement that this was a bad sign. They called the ECG reading a Left Main Equivalent.
They said that ST segment elevation in AVR is a significant predictor of mortality in the setting of an MI. AVR lacks a contiguous lead, but as I understand it now, it is reciprocal to leads V4, V5, V6, as well as leads I and II. It provides a view of the endocardial area of the left ventricle and the apex as well as the base of the septum. ST elevation in AVR can be indicative of an occlusion of the Left Main Coronary Artery and/or significant three vessel disease.
In other words, patients presenting with possible ACS who have ST elevation in AVR should be treated very seriously.
What I love best about being a paramedic is not only learning new things, but then applying those lessons to my patients in the field.
Check out this ECG of a patient with chest pain:
The patient had extensive three vessel disease including a near 100% occlusion of the LAD and ended up requiring a triple bypass to restore adequate perfusion.
Here is some more information on AVR:
Note: An check out the excellent comments below by Christopher that detail more uses of aVR.