Wednesday, 7 June 2017

ECG of the Week - 5th June 2017 - Interpretation

The following ECG is from a 66 yr old female who presented to the Emergency Department complaining of dizziness and pre-syncope. She is awaiting an out-patient colonoscopy and had just completed her bowel prep.



Click to enlarge
Rate:
  • 66 bpm
Rhythm:
  • Regular
Axis:
  • Normal
Intervals:
  • PR - Normal (~200ms)
  • QRS - Normal (80ms)
  • QT - 400ms (QTc Bazette 420 ms)
Additional:

  • Partial RBBB Morphology
  • Prominent U waves leads I, II, aVF, V4-6
  • T-U fusion in lead III & V2
  • Causing pseudo QT prolongation if these leads are used to measure QT

Interpretation:

  • Features favor hypokalaemia
    • U waves
    • T-U fusion
    • Clinical scenario of likely large fluid shifts secondary to bowel prep


What happened ?


The patients had a combination of hyponatraemia and hypokalaemia (2.4 mmol/L) and following electrolyte / volume correction her symptoms resolved. Repeat ECG showed resolution of U waves.

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.