ECG of the Week – 2nd April 2018 – Interpretation

The following ECG is from a 74yr old male who presented following several episodes of chest pain and dizziness. 

Click to enlarge


  • 66 bpm


  • Nil p waves
  • Fibrillation waves best seen leads V1 & V3
  • Regular ventricular rhythm 
  • Each ventricular complex associated with a pacing spike
    • Best seen leads II, aVR, aVF, V1, V3-6


  • Left
    • Superiorly at ~ -70 degrees


  • QRS – Prolonged (200ms)


  • Appropriate discordant T wave and ST changes
  • No evidence of excessive discordance
  • Note QRS relatively low voltage in leads V1-2
  • Need to check ECG lead placement
  • Compare with old ECGs
  • Monitor for dynamic change


  • Ventricular paced rhythm
    • All complexes paced
    • Absence of native rhythm
    • Lead placement likely right ventricular apex
    • Nil atrial activity seen
 Quick pacemaker points
Remember a few things about patients with pacemakers.
Pacemaker activity visualised on the 12-lead is dependent on several factors:
  • Pacemaker programming
  • Patient’s current native rhythm
  • Wire placement
  • Appropriate wire position and function
  • Patient’s other activity co-morbidities – drug toxicity, ACS, electrolyte abnormality etc.
What might you see:
  • No pacing activity / Native rhythm only
  • Atrial pacing only
  • Ventricular pacing only
  • Combination of atrial and ventricular pacing
  • Combination of all the above

References / Further Reading

Life in the Fast Lane


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

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