To ensure the best quality ECG you should make sure the patient is relaxed. If the patient is tense this can affect the ECG, as muscle tremor can be misinterpreted. Remember, decisions are made based on this ECG reading.
Watch the ECG video clips and move through the slides using the < > controls below:
Baseline wander
The ECG should have a steady baseline.
To eliminate baseline wander:
- Patient breathing should be steady and shallow
- Patient should not talk
- Check that all tabs are in good contact with the skin
As a last resort the patient can be asked to stop breathing whilst the ECG is recorded and told to resume breathing immediately the recording is finished. Prior to this, you should ensure that all preparations are complete and that you are set to record the ECG without delay.
Poor lead electrode contact
This may show as baseline wander or even a flat line in some leads.
Check:
- All tabs are in fully in contact with the skin
- That tabs are not dried out and therefore not conducting
- That the ECG cable/clips are not pulling on the tabs
Good skin preparation is important to obtaining a good quality ECG.
Muscle (somatic) tremor
This shows in the ECG as irregular spiky interference, generally within the limb leads. Tremor may only be present in some leads e.g. Lead 1 and this would indicate tension in the right and/or left arms. Muscle tremor is confined to the limb leads.
Check:
- Patient’s shoulders are relaxed
- Arms are relaxed at their side and hands/fingers are still and not clenched
- Ensure patient is not cold/shivering
- Patient is not talking
For patients who have pathological limb tremor, e.g. Parkinson’s disease, hands can be slipped under the buttocks to reduce tremor.
IMPORTANT: Muscle tremor can adversely affect the computerised interpretation and can result in a false report.
AC interference
This shows as a thick black line with regular 50Hz interference on the ECG, giving a “fuzzy” appearance to the tracing, and will appear in limb and chest leads.
It comes from external sources and can be eliminated by switching off any NON ESSENTIAL electrical equipment in the near vicinity for the duration of the recording.
If you are in a ward area/HDU/ITU check with staff before switching off any equipment.
Normal ECG
A good quality ECG will have a steady baseline, with no muscle/somatic tremor and no AC interference. All relevant information on the patient should be provided to aid correct interpretation. Any deviation from standard practice should be noted on the ECG.
Pulse point
Reflect on how important good practice in ECG recording is in order to ensure the correct diagnosis can be made quickly and accurately as possible.
A useful site for further ECG examples is ECG Library.
Page last reviewed: 21 May 2020
