Wednesday, 2 January 2013

ECG of the Week - 31st December - Interpretation

A bit of a departure from the normal to herald in the New Year.


 
This week we have a rhythm strip I found.
 
I don't have any information on the case, patient, or management.
 
So what you see is what you get !
 
 
 

 


 
Click to enlarge

Two lead rhythm strip, leads II & V2, assuming standard calibration.

 
Three distinct rhythms:
 
Rhythm 1



  • Ventricular Rate ~150-100 bpm
  • Regular Atrial activity ~300 bpm (Flutter waves)
  • Variable conduction block - 2:1 & 3:1
  • Intervals
    • No P waves
    • QRS - Normal (~ 100ms)
  • Segments
    • ST Depression lead II
    • ST Elevation V2
  • Additional
    • Abrupt termination without preceding slowing of rate, or increasing block

Rhythm 2
  • Asystole
  • Duration ~4.9 seconds

Rhythm 3

  • Sinus rhythm
  • Irregular due to rate change
    • ~70 bpm to ~80 bpm
  • Intervals:
    • PR - Normal (~160ms)
    • QRS - Normal (100ms)
    • QT - 400ms (QTc Bazette ~ 460 ms)
  • Segments:
    • ST Depression 1mm lead II
    • ST Elevation 3-4mm lead V2
  • Additional
    • P wave inversion V2
 
Interpretation:

  • Atrial flutter with variable block
  • Period of aystolic pause
  • Followed by sinus rhythm at appropriate rate
  • ST Segment changes - ? ischaemic ? hypertrophy
I don't have any clinical information on this case, differentials for these finding could include:

  • Iatrogenic
    • Chemical cardioversion
    • Correction of underlying acid/base or electrolyte disturbance
  • Sinus Node Dysfunction
Waitng to hear some of the thoughts of the 'ECG of the Week' team on this one, I will update this post once all the team has had chance to have a look.
 
References / Further Reading 

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