ECG of the Week – 28th January 2019 – Interpretation

The following ECG is from an 18 yr old female who presents with ongoing weight loss with a known eating disorder. Her weight is 33 kg (72 lbs) with a BMI of ~13.



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Rate:

  • 36 bpm

Rhythm:

  • Sinus rhythm
  • Sinus arrhythmia

Axis:

  • Inferior 

Intervals:

  • PR – Normal (~170ms)
  • QRS – Normal (100ms)
  • QT – 490ms 
    • QTc Bazett 380ms
    • QTc Hodges 450ms
    • QTc Framingham 290ms

Additional:

  • T inversion aVL with negative QRS
  • T wave inversion leads V1-2
  • No ST depression

Interpretation:

  • Significant sinus bradycardia


ECG and Cardiac Abnormalities associated with eating disorders

ECG and cardiac abnormalities associated with eating disorders can be multi-factorial and related to:

  • Loss of cardiac muscle – cardiac failure, mitral valve prolapse
  • Electrolyte abnormalities – hypokalaemia, hypomagnesaemia
  • Chronic nutritional deficit – cardiomyopathy
  • Parasympathetic overdrive – bradycardia, hypotension
  • Dehydration / volume depletion – hypotension
  • Medication use / abuse – laxatives, sympathomimetics, anti-depressants, anti-psychotics
  • Secondary to treatment – re-feeding syndrome, electolyte abnormalities

ECG features are secondary to the issues listed above and include:

  • QT / QTc prolongation with associated risk of TdP and Sudden cardiac death
  • Severe bradycardia
  • AV block
  • T wave abnormalities – usually associated with electrolyte abnormality
  • Low voltage

Mainstay of treatment is correction of electrolyte abnormality and encourage nutritional intake and weight gain whilst monitoring for re-feeding issues.

References / Further Reading

Life in the Fast Lane

Textbook

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

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