The ECG shown on page 11 (Figure 1) is from a 41-year-old female admitted for management of anorexia.

a) List the ECG abnormalities. (10% marks)

b) Give the underlying cause. (10% marks)

c) List four other ECG abnormalities that may be seen in this condition. (10% marks)

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College answer

a)  
ST depression 
T    wave flattening and inversion 
U    waves  
Long QT/QU interval (fusion of T and U waves) 
 
b)    Hypokalaemia 
 
c)    
P wave amplitude increased (>2.5 mm in limb leads, >1.5 mm in chest leads) 
P wave width increased (>120 msec) 
PR interval prolonged (>200 msec) 
Supraventricular ectopics 
Ventricular ectopics 
Atrial fibrillation 
Atrial flutter 
Atrial tachycardia 
Torsade de pointes 
 

Discussion

The ECG above was stolen from the LITFL archive.

ECG findings of hypokaelmia:

  • Ventricular tachycardia: classically, torsades de pointes
  • Atrial tachycardias
  • PR interval prolongation (>200 msec)
  • P wave amplitude increased (>2.5 mm in limb leads, >1.5 mm in chest leads) - a "pseudo-P-pulmonale" pattern
  • P wave width increased (>120 msec)
  • u-waves (thpough these are not unique to hypokalemia: they are associated with LVH, bradycardia and may occasionally be a normal variant)
  • T-wave inversion
  • Ectopics (ventricular and atrial)

References

References

Norgard, Nicholas, Amanda McEvoy, and Thomas Madejski. "Influence of Pharmacologic Agents and Electrolytes on ECGs." Clinical Exercise Electrocardiography (2015): 173.