|Click to enlarge|
Things to think about
- What are the key ECG abnormalities ?
- How could you improve the quality of the patient's ECG ?
- 60 bpm
- Sinus rhythm
- PR - Normal (~200ms)
- QRS - Prolonged (120ms)
- RBBB Pattern
- Baseline wander in limb leads ? U waves
- Significant high frequency artefact obscuring majority of details in precordial leads
- Sinus rhythm with RBBB
- Significant artefact obscuring rest of ECG interpretation
There are multiple factors that can generate artefact during the ECG recording / printing process including:
- Patient factors
- Implanted devices
- PPM - Pacing Spikes
- Nerve stimulators
- Movement disorders e.g. Parkinson's, essential tremor
- Muscle tremor / activity can be related to pain, hypothermia etc.
- Habitus - very thin or obese patients, paediatric patients
- Poor pad contact due to hair
- Poor pad contact due to moisture - sweating, immersion etc.
- Lead factors
- Poor pad contact
- Pad misplacement
- Damaged lead or lead connection
- ECG Machine Factors
- Inappropriate settings of gain or filtering modes
- Electrical artifact from power supply
- Printing factors
- Low ink
- Print head tracking
- Paper alignment
- External factors
- Interference from surrounding electronic devices. Relatively rare using newer ECG machines and environmental interference is usually compounded by incorrect machine filter settings.
An awareness of these factors and a systemic approach to addressing each point in the recording process, from patient to printer, is important in addressing recording problems such as artifact and lead mal-positioning.
References / Further Reading
Life in the Fast Lane
- Chan TC, Brady WJ, Harrigan RA, Ornato JP, Rosen P. ECG in Emergency Medicine and Acute Care. Elsevier Mosby 2005.