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

• Hypokalaemia
• QT Interval / QT Prolongation

Textbook

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