Wednesday, 1 August 2018

ECG of the Week - 30th July 2018 - Interpretation

This ECG is from a 69 yr old female who presented complaining of palpitations. She has a background of paroxysmal AF and her medications include a NOAC.



Click to enlarge
Rate:
  • Mean ventricular rate 96 bpm
Rhythm:
  • Bigemny
    • Sinus complex following by unifocal PVC in 1:1 relationship
Axis:
  • Normal
Intervals - sinus complexes:
  • PR - Normal (~140ms)
  • QRS - Normal (80ms)
Additional:
  • ST Depression leads I, II, III, aVF, V4-6
  • ST Elevation leads aVR and aVL
  • Significant baseline wander

There are multiple causes of PVC's and bigeminy including:

  • Anxiety
  • Altered sympathetic tone
  • Drug toxicity especially digoxin
  • Excess caffeine
  • Electrolyte disturbance
  • Ischaemia
  • Myocarditis
The presence of bigeminy can be very distracting and careful review of the ECG is required to make sure you're not missing anything. The presence of ST / T wave changes can be easily missed due to the expected ST segment abnormalities associated with PVC's creating a visual distraction. 
I like to cover up the PVC's with a bit of paper so I can focus on the sinus complexes and then do the same for the sinus complexes as the PVC's can sometimes give additional clues as to what's going on. I think the ST changes in the sinus complexes are easier to appreciate when the PVCs are removed in the image below.

Click to enlarge
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.