Wednesday, 15 January 2014

ECG of the Week - 13th January 2014 - Interpretation

This week's ECG is from a 72yr old with known atrial fibrillation and a PPM in situ. He presents with several days of atypical chest pain. Medications include metoprolol, frusemide, and low molecular weight heparin (intolerant of warfarin).
Check out the comments on the original post here.

Click to enlarge

  • Mean ventricular rate ~78 bpm
  • Irregularly irregular native ventricular activity
  • Nil clear p waves
    • Irregularity to baseline in leads II, III, V1-2
  • Single ventricular paced complex
    • Complex #6
  • Normal
Intervals Native Complexes:
  • QRS - Normal (~70ms)
  • QT - 380ms
Intervals Paced Complex:
  • QRS - Prolonged (120ms)
  • QT - 420ms

  • ST Elevation aVR
  • ST Depression leads I, II, V4-6
  • Discordant ST segment change in paced complex


  • Paced complex occurs 1000ms following R wave peak of preceding complex
  • T wave inversion leads II, III, aVF, aVL, V4-5
  • Undulating baseline in inferior and precordial leads 
    • ? flutter vs U waves vs artifact


  • Rate controlled atrial fibrillation
  • Single paced complex
  • ST / T wave changes non-diagnostic, consider
    • Ischaemia
    • Drug effects esp. digoxin
    • Electrolyte abnormality
    • Doesn't quite meet voltage criteria for LVH

What happened ?

Serial ECG's showed no dynamic changes, and serial troponins were negative.
Medication review confirmed the patient was not on digoxin.
He was discharged from the Emergency Department with planned out-patient cardiology follow-up with his usual specialist.

Sorry for the anti-climactic ending but the truth is that this is what happens to a significant portion of the patients we see with chest pain, non-dynamic longstanding ECG abnormalities, and negative cardiac biomarkers.

References / Further Reading

Life in the Fast Lane

  • Digoxin and the ECG here
  • Left ventricular hypertrophy here
  • Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.

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