ECG of the Week – 23rd April 2018 – Interpretation

The following ECG is from a 41yr old male who was referred to telehealth from a rural center ~1500 km  (930 miles) from the nearest major hospital.

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  • 48 bpm


  • Sinus arrhythmia
  • Sinus rhythm


  • Normal


  • PR – Normal (~200ms)
  • QRS – Normal (80ms)
  • QT – 410ms (QTc Bazette 370ms)


  • Early R wave transisition
  • Borderline voltage criteria LVH
    • V1 S + V5 R ~35mm
    • No non-voltage criteria present


  • Sinus bradycardia with sinus arrhythmia

Considerations with sinus bradycardia

I get asked to review many ECG’s that show sinus bradycardia and there are a few considerations in these cases including:

  • Is the patient symptomatic ?
  • Is this ‘normal’ for the patient ?
  • What is / could be the cause ?

Regarding symptoms these may be the reason for an Emergency Department attendance or more insidious and can include:

  • Syncope
  • Dizziness
  • Light headedness
  • Dysponea
  • Decreased exercise tolerant
  • Lethargy
  • Palpitations
  • Chest pain

There are multiple potential causes of bradycardia including:

  • Physiological – athletes or during sleep
  • Increased vagal tone – nausea, vomiting, pain
  • Ischaemia
  • Drug effect / toxicity – inc, digoxin, beta-blockers, calcium channel blockers
  • Environmental – hypothermia
  • Endocrine – hypothyroid
  • Myocarditis
  • Sinus node dysfunction
  • Sleep apnoea

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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