ECG Motion Artefacts

Introduction

  • Motion artefact due to tremor or shivering can obscure the waveforms of the ECG or simulate pathology, making ECG interpretation difficult.
  • In certain circumstances (e.g. hypothermia), the presence of shivering artefact may actually aid diagnosis.

Causes of Tremor

  • Benign Essential Tremor (physiological tremor)
  • Parkinson’s Disease (resting tremor)
  • Cerebellar disease (intention tremor)
  • Alcohol / Benzodiazepine withdrawal
  • Anxiety
  • Thyrotoxicosis
  • Multiple sclerosis
  • Drugs: Amphetamines, cocaine, beta-agonists (adrenaline, salbutamol), theophylline, caffeine, lithium.

Other types of motion artefact

  • Fever (rigors)
  • Hypothermia (shivering)
  • Cardiopulmonary resuscitation (chest compressions)
  • A non-compliant, mobile, talkative patient (= the most common cause)!

 

ECG Examples

Example 1

Hypothermia:

 

Example 2

Parkinsonian tremor:

  • The irregular baseline in this ECG gives the appearance of atrial fibrillation.
  • The slow regular rhythm even suggests the possibility of atrial fibrillation with complete heart block and a junctional escape rhythm.
  • However, on closer inspection there are visible P waves in V3 (circled).
  • This patient had sinus bradycardia and a resting tremor due to Parkinson’s disease.

 

Example 3

Chest compressions during CPR:

  • The high amplitude oscillations at the start of the rhythm strip are produced by movement artefact due to chest compressions during cardiopulmonary resuscitation.
  • The second half of the rhythm strip shows ventricular fibrillation – presumably at this point the resuscitating team have stopped CPR to reassess the rhythm!

 

Example 4

Precordial thump:

  • This ECG demonstrates the movement artefact produced by a precordial thump!

 

Further Reading

Author Credits

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