Wednesday 26 February 2014

ECG of the Week - 24th February 2014 - Interpretation

This week's ECG is from a 62 yr old male who presented complaining of palpitations for the preceding 4 hours. No significant medical history or medications.
Check out the comments on our original post with some interesting discussion.

Click to enlarge
Rate:
  • Ventricular rate ~145 bpm
  • Atrial rate ~290 bpm
Rhythm:
  • Regular
  • Flutter waves
    • Best visualised lead V1
Axis:
  • LAD
Intervals:
 
  • QRS - Prolonged (140ms)
  • QT - 320ms
Segments:
  • Discordant ST elevation leads II, aVF, V1-5
  • Discordant ST depression leads I, aVL, V6
Additional:
  • Typical LBBB morphology
  • T wave inversion leads I, aVL
  • Positive F wave lead V1
  • Negative F waves aVF
Interpretation
  • Atrial flutter with 2:1 conduction
    • Could be atrial tachycardia / atypical flutter (i.e. not right cavotricuspid isthmus related) given small F waves and relatively long isoelectric segment.
  • Left bundle branch block
    • This could be pre-existing or rate related, I don't have a sinus ECG to compare.
You can read about various classifications in this paper:
  • Medi C, Kalman JM.Prediction of the atrial flutter circuit location from the surface electrocardiogram.Europace. 2008 Jul;10(7):786-96. PMID: 18456647 Free text here

VT vs SVT

In this ECG the morphology of the conduction delay is typical of left bundle branch block without any features suggestive of VT with LBBB, see Life in the Fast Lane and ECGpedia links below.Also examination of lead V1 shows flutter waves at a rate of ~290 bpm.
Lead V1 with atrial activity marked (red arrows)
 You can check out more on differentiating VT from SVT in a number of other blogs and posts, selection below:

References / Further Reading
 
Amal Mattu's EKG VIdeos
 Life in the Fast Lane
  • Atrial Flutter here
  • Atrial Fibrillation here
  • Left Bundle Branch Block here
  • VT vs SVT with Aberrancy here
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.
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