Saturday, 25 January 2014

Axis in Practice: Case Study 2

Case Study 2

Whether you are a beginner or an instructor it's useful to have these two 12-lead ECGs in your collection. The first ECG demonstrates an extreme axis deviation; this may also be referred to as "north west" or "no man's land" axis. Some instructors deem that "extreme" may wrongly imply an extreme cause of the axis deviation. This is worth noting here! The second ECG demonstrates a right axis deviation. However, both show a negative/inverted PQRST complex in lead I. What is your interpretation of each ECG?

Many thanks for reading, and as always please feel free to share...Mx

Hola a todos nuestros amigos de habla hispana, nos esforzaremos en traducir nuestros blogs lo más pronto posible! Gracias...Mx


  1. The upper ECG appears to have been recorded with the left arm and right arm connections transposed. This should not affect the chest lead appearances, but the R wave progression here is not quite normal, so perhaps the chest electrodes were not positioned entirely correctly.
    The lower ECG looks as if it was recorded from someone with dextrocardia. The chest lead QRS complexes are all negative and diminish in amplitude from V2 to V6.

    1. I agree. I'd like to add some comments.
      Upper ECG. Signs of connections transposition: i) positive P wave in aVR, ii) QRS complexes in I and V6 look completely different (in normal ECG they have to be similar)
      And respectively the lower one: i) you see negative P in aVR (QRS is isoelectric, so it may look quite weird), ii) QRS in I and V6 are negative, both start with small r, you see positive T waves. Basing on these two features you may exclude transposition of limb leads.

      Thank you again for ECGs.

  2. Thank you for your comments. Yes, the first ECG was recorded with the left and right arm electrodes swapped (sometimes referred to as "technical dextrocardia"). The second ECG was recorded from a patient with true dextrocardia. As quite rightly pointed out a true dextrocardia will demonstrate diminishing complexes in the chest leads, which reflects the main electrical vector moving away from those leads. Thanks again :)