Wednesday, 5 April 2017

ECG of the Week - 3rd April 2017 - Interpretation

The following ECG is from a 48 yr old male who attended the Emergency Department following an electric shock. The electricity source was a 240V AC domestic supply and the patient sustained a minor burn to his hand.



Click to enlarge
Rate:
  • 54 bpm
Rhythm:
  • Regular
  • Sinus Rhythm
Axis:
  • Normal
Intervals:
  • PR - Normal (~120ms)
  • QRS - Normal
  • QT - 420ms
Segments:
  • ST Elevation leads aVR, V1-2
  • ST Depression leads II, aVF, V4-6
Additional:
  • Deep T wave inversion leads V2-6
    • Terminal positive deflection to T wave in these leads ?U wave
  • T wave inversion leads I, II, aVF
  • Massive R waves in all precordial leads
Interpretation:
  • Extensive T wave abnormalities with massive precordial complexes
The differential for these ECG features given the clinical scenario would be:
  • Electrical injury related
  • Incidental finding of cardiomyopathy ( ECG pattern favours apical variant)
What happened ?

On history review the patient had no history of loss of consciousness, syncope, palpitations or chest pain related to his presenting injury. There was a positive family history of cardiomyopathy in a close relative but no history of sudden cardiac death.
The patient was admitted under cardiology for further investigation.
The patient had negative serial troponins and underwent angiogram which showed:
  • Normal coronary arteries
  • Normal LV function
  • ? Apical hypertrophy
Subsequent echo showed:
  • Normal LV cavity size and function
  • Asymmetric distribution of left ventricular hypertrophy affecting the apical LV region
The patient's investigation findings are consistent with apical hypertrophic cardiomyopathy, sometimes referred to as Yamaguchi Syndrome. He was discharged with ongoing cardiology follow-up.

You can read more about apical hypertrophic cardiomyopathy in the links below:

What about the electrocution ?

There are a wide variety of ECG features that have been reported in the setting of electrocution including:
  • Arrhythmia - AF, VT, VF
  • AV Block - all types
  • ST / T wave changes
  • QRS Abnormality
The following study reviewed the role of cardiac monitoring after an electrical injury and suggests that those patients who are asymptomatic with no loss of consciousness following a low voltage (<1000v a="" cardiac="" do="" ecg="" font="" monitoring.="" normal="" not="" ongoing="" require="" shock="" with="">

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.