Wednesday, 6 February 2013

ECG of the Week - 4th February 2013 - Interpretation


It's time for an ECG trilogy.


Over the next 3 weeks we have a series of ECG's from a single patient.
 

69 year old female presenting with palpitations and mild dysponea. 
Nil chest pain, no overt cardiac failure, and an acceptable blood pressure. 
History of cardiomyopathy, chronic AF, LVF, and has an ICD in-situ.





 

 
Click to enlarge




 
 
Rate:
  • 150
Rhythm:
  • Regular
  • No R-R variability

Axis:
  • LAD (-55 to -60 deg)
Intervals:
  • QRS - Broad (~160ms)
  • QT - 320ms (QTc Bazette ~ 505 ms)
Segments:
  • Discordant ST segment changes
    • ST Elevation III, aVF, aVR, V1
    • ST Depression I, aVL,V2-6
 
Additional:
  • Positive concordance pre-cordial leads
  • Notching best visualised in leads V4-6 at beginning of ST segment and as T wave returns to baseline at rate of 300 bpm

 Interpretation:

  • Broad complex tachycardia
  • Differentials:
    • VT - concordance, older patient, Hx cardiac disease
    • Atrial Flutter - given rate of 150 bpm and ? flutter waves in lateral leads, although QRS morphology atypical ? accessory pathway / pre-excitation
    • Other differentials of broad complex tachy - less likely given atypical QRS morphology & rate
 

What happened next ?
  • Magnet - no effect,
  • Adenosine - no effect,
  • Amiodarone - rhythm changed ... we'll have a look next week !
I'm waiting to here back from our cardiologists on their thoughts for this one.
I've referenced two articles below if any of our readers want to read more about how ICDs decide when to deliver a shock.

References / Further Reading


 
Life in the Fast Lane


Articles

  • Swerdlow CD, Friedman PA. Advanced ICD troubleshooting: Part I. Pacing Clin Electrophysiol. 2005 Dec;28(12):1322-46. PMID: 16403166
  • Swerdlow CD, Friedman PA.Advanced ICD troubleshooting: Part II. Pacing Clin Electrophysiol. 2006 Jan;29(1):70-96. PMID: 16441722
 
Textbook
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.