Wednesday, 22 February 2012

ECG of the Week - 20th Feb 2012 - Interpretation

This week we had a single ECG for review with no clinical information

Whilst clinical correlation with any  investigation is necessary we often get ask to review ECG's 'hot of the press' for patients that haven't been assessed yet and a structured approach in these scenarios is even more important.

On to this weeks ECG.

Click to enlarge

  • 150
  • Regular without p waves
  • LAD (-39 deg)
  • PR - No visible p waves
  • QRS - Normal (100-120ms)
  • QT - 280ms (QTc Bazette 440ms)
  • Possible ST depression V3-6
  • Flutter waves visible in V1
  • T Wave Inversion V1-2, aVL
  • LVH (aVL>11mm)


  • Narrow Complex Tachycardia
  • Ventricular rate 150bpm
  • Atrial Flutter 2:1 Block
  • Other differentials include AVNRT / AVRT however the rate is usually higher in these
  • 'Mapping' of flutter waves may be helpful, this may be easier if paper speed is altered e.g. 50mm/sec
  • Trial of vagal manoeuvers of adenosine may help differentiate Atrial Flutter
  • This patient recieved adenosine, rhythm strip below, revealing obvious flutter waves.

Click to enlarge

Would the Lewis Lead have helped ?

  • Described by Sir Thomas Lewis in 1931
  • Place RA electrode on right sternal edge 2nd intercostal space
  • Place LA electrode on right sternal edge 4th intercostal space
  • Lead I then principally reads atrial electrical activity
  • May help magnify flutter or fibrillatory waves
  • May benefit from increasing gain and adjusting paper speed to 50mm/sec
  • Listen to the excellent EMCrit podcast on the Lewis Lead here
  • Or read more about it here

References / Further Reading

Life in the Fast Lane
  • Atrial Flutter Here
  • Left Ventricular Hypertrophy Here
Dr Smith's ECG Bog
  • What's the rhythm ? Here
  • ECG Quiz - Unusual Flutter Here
  • Bakker AL, Nijkerk G, Groenemeijer BE, Waalewijn RA, Koomen EM, Braam RL, Wellens HJ. The Lewis lead. Circulation. 2009 Jun 23;119(24):e592-3. Full Text
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.

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