ECG Motion Artefacts Overview
- 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
- 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)!
- This ECG displays the classic features of hypothermia: bradycardia, Osborn waves and shivering artefact.
- 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.
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!
- This ECG demonstrates the movement artefact produced by a precordial thump!
LITFL Further Reading
- ECG Library Basics – Waves, Intervals, Segments and Clinical Interpretation
- ECG A to Z by diagnosis – ECG interpretation in clinical context
- ECG Exigency and Cardiovascular Curveball – ECG Clinical Cases
- 100 ECG Quiz – Self-assessment tool for examination practice
- ECG Reference SITES and BOOKS – the best of the rest
- Brady WJ, Truwit JD. Critical Decisions in Emergency and Acute Care Electrocardiography
- Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric
- Wagner GS. Marriott’s Practical Electrocardiography 12e
- Chan TC. ECG in Emergency Medicine and Acute Care
- Rawshani A. Clinical ECG Interpretation
- Mattu A. ECG’s for the Emergency Physician
- Hampton JR. The ECG In Practice, 6e