ECG Challenge 4 - the Axis

A 65 years old lady was referred from a peripheral center with this ECG, she had no symptoms and the ECG was an incidental finding.

What is your opinion on the ECG? The Axis is clearly not right and there seem to be no R waves in the chest leads.

If you look at the Axis first, the leads I, II, aVL are all negative. In particular the lead I shows inverted P waves as well.

Lead I. Inverted P waves are highlighted with an arrow

This 'Extreme' Axis deviation alongwith the Positive aVR leaves us with 2 major possibilities: Lead reversal or Dextrocardia!

Now notice the chest leads:

You can notice a relatively positive R wave in V1, after that the R wave actually regresses in size. This leaves only Dextrocardia as a possibility.

The patient indeed had Dextrocardia with Situs Inversus which was conformed on examination and a Chest X-Ray. Dextrocardia with sinus inversus, being the mirror image of the normal (Levocardia with situs solitus, is not associated with any complications. The other variation, Dextrocardia with Situs solitus, is associated with major complications and the patients present in early childhood.