Tricky ekg this week! Hopefully, you were concerned about the patient given his history of an MI and story of index chest pain. Ideally, the first thing jumping out at you is the ST elevations in I and aVL. So it’s a STEMI, right?
Not so fast. This EKG is an excellent example of why you need to have a method for every EKG that you read. Start at the basics.
- Rate: slightly tachy at 105 ish
- Rhythm: P before each qrs, upright in lead II, NSR
- Axis: Down in I, up in aVF, Right axis… But wait a second, those P waves are inverted in I…
- Looking closer, aVR is UPRIGHT, which is super weird…
- Let’s take a closer look, we have STE in I and aVL, but we’re seeing some depressions in V5 and V6… That doesn’t make sense either. Something is wrong with this ekg.
- That’s right! The limb leads are reversed! This is from life in the fast lane:
Quick guide to spotting LA/RA reversal
- Lead I is completely inverted (P wave, QRS complex and T wave).
- Lead aVR often becomes positive.
- There may be marked right axis deviation.
LA/RA reversal may simulate dextrocardia. However, in contrast to dextrocardia there is normal R wave progression in the precordial leads.
Take a look at this ekg, with the limb leads not reversed!
Crazy, right?! Stay sharp!