Wednesday, 13 September 2017

ECG of the Week - 11th September 2017 - Interpretation

This ECG is from a 45 yr old who was found in a collapsed state in the street.



Click to enlarge
Rate:
  • 66 bpm
Rhythm:
  • Regular
  • No clear p waves
Axis:
  • Normal
Intervals:
  • QRS - Prolonged (240ms)
  • QT - 520ms (QTc Bazette 545 ms)
Additional:

  • J waves leads II, III, aVF, V2-6
  • ST Depression leads II, III, aVF, V4-5
  • Subtle ST elevation leads aVR and aVL
  • T wave inversion leads II, III, aVF
  • Biphasic T lead V4-5 possible T-U fusion

Several differentials for these ECG features especially given clinical scenario including:

  • Hypothermia - must likely - junctional / escape rhythm, J waves, QT & QRS prolongation
  • Intracerebral pathology - clinical collapse, can cause J waves and QT prolongation
  • Drug toxicity - loss of normal sinus rhythm, can cause J waves, QRS and QT prolongation, also can be a cause of hypothermia

Remember J waves are not pathognomonic of hypothermia and can be seen in association with hypercalcaemia and raised ICP. 

What happened ?

The patient had multiple acute medical issues:

  • Severe hypothermia - core temperature 25.9 C (78.6 F)
  • Coma - GCS 3 (E=1, M=1, V=1)
  • Hyperkalaemia (7.2 mmo/L) and acute renal failure
  • Hepatic failure with coagulopathy
  • Likely polypharmacy overdose

Despite early aggressive resuscitation, rewarming and renal replacement therapy the patient had progressive multi-organ failure and did not survive.

Causes of hypothermia

There are multiple potential causes of hypothermia including:
  • Cold water immersion
  • Cold / wet / windy environments
  • Exhaustion
  • Excessive activity e.g. marathon runners
  • Head injury
  • Trauma inc. entrapment
  • Immobility +/- trauma
  • Major burns
  • Drugs inc. sedatives, alcohol, phenothiazines
  • CVA
  • Parkinson's disease
  • Sepsis
  • Endocrine inc. adrenal insufficiency, hypothyroid, hypoglycaemia
  • Malnutrition
  • Iatrogenic inc. massive transfusion, fluid resuscitation, exposure
  • Age - elderly and neonates

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.