ECG of the Week - 10th February 2014 - Interpretation

This week's ECG is from a 39 yr old female who presented to the Emergency Department with vomiting, diarrhoea, and upper abdominal pain.
You can view the lab investigations from this patient over at our sister site Emergucate in this week's Lab Case of the Week from Dr Yusuf Mamoojee.
Check out the comments from our original post here.

Click to enlarge

Rate:

• 60 bpm

Rhythm:

• Sinus arrhythmia

Axis:

• Normal

Intervals:

• PR - Normal (~150ms)
• QRS - Prolonged (120ms)
• Apparent QT - 680ms (QTc Bazette ~ 670 ms)

Segments:

• ST Elevation lead aVR (1mm)
• ST Depression leads II, III, aVF, V3-6

Additional:

• Prominent U waves
• T-U Fusion
• Best visualised in leads II, III, aVF, V3-6
• Initial T wave is inverted and merges with large U wave
• Results in apparent QT prolongation due to fusion
• Best considered QU prolongation

Interpretation:

Features consistent with hypokalaemia +/- hypomagnesaemia

The patient's potassium was 2.2 mmol/L and magnesium 0.9 mmol/L.
You can check out the rest of the patients bloods and the interpretation over at Emergucate's Lab Case of The Week #6.

Hypokalemia ECG's on the Web

• ECG of the Week - We've had some examples of hypokalemia previous check them out here & here.
• Dr Smith's ECG Blog - multiple great examples of hypokalaemic ECGs here.
• Dr Ken Grauer's ECG Interpretation - A great walk through of ECG changes in hypokalaemia here.
• Amal Mattu's ECG Video - ECG findings in severe hypokalaemia here.

References / Further Reading

Life in the Fast Lane

• Hypokalaemia here
• Hypomagnesaemia here

Textbook

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