Wednesday, 19 July 2017

ECG of the Week - 17th July 2017 - Interpretation

The following ECG is from a normally fit and well 10 yr old female who presented with chest pain. She has normal vital signs and a normal chest x-ray.

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  • 78 bpm
  • Regular
  • Sinus rhythm

  • Extreme / NW
  • PR - Short (100-120 ms)
  • QRS - Normal (100ms)
  • QT - 320ms 
  • Abnormal Precordial R wave progression
    • Positive R wave V1 then negative V2 then positive V3-6
    • Deep S wave in inferior leads
  • T wave inversion leads III, aVF
  • Deep Q waves leads V1, V2-6
  • Abnormal aVR dominant terminal R wave
  • Very high precordial QRS voltages


  • Very abnormal ECG
    • Abnormal axis, voltages, QRS morphology

Remember we should always take the ECG differentials in the context of the clinical scenario. The majority of chest pain in children in benign in nature and this child had no history of cardiac disease. The presence of axis abnormality should always prompt consideration of lead reversal especially in the setting of a clinical picture and ECG disconnect. In this patient virtually every ECG lead was placed and connected in the wrong order ! Following correction of the lead reversals a repeat ECG was performed:

Click to enlarge
We now have a normal axis, normal R wave progression with resolution of the abnormally high QRS voltages and Q waves. We do see a rhythm abnormality with an ectopic atrial rhythm during complexes #4-7. If the ectopic atrial rhythm persisted during the 1st ECG recording it may explain why we didn't seen the complete (P, QRS,T) inversion we usually associated with lead misplacement.

References / Further Reading

Life in the Fast Lane

  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005

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