- 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)!
- 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!
- ECG BASICS — Waves, Intervals, Segments and Clinical Interpretation
- ECG CLINICAL CASES — Your favourite ECG’s placed in clinical context with a challenging Q&A approach
- ECG and Cardiology Eponymous Syndromes — Cheats guide to eponymous emancipation
- ECG Exam Template — a framework for the FACEM part 2 exam.
- ECG Reference Sites on the WEB — the best of the rest