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In rehab, the ECG signal is evaluated for its quality. The program analyses the signal quality separately for each ECG channel (see calculation of the ECG signal quality) and assigns one of the following signal qualities every second:
| ECG signal quality | Example ECG signal | Score value in |
|---|
| information block | Description | ||
|---|---|---|---|
| good ECG quality |
| E:1 | ECG must look like this, with such an ECG signal there are guaranteed no problems with the QRS detection |
| sufficient ECG quality |
| E:3 | This ECG quality means that the QRS detection will still recognize every QRS complex due to internal filtering, but it is already an indication that one or the other QRS complex may be overlooked here. |
| insufficient ECG quality |
| E:6 | This ECG quality means that the QRS detection is certainly "overlooked" despite the internal filtering of some QRS complexes (false negative) or disturbances of the ECG signal even as QRS detection (false positive). |
| non-physiological ECG quality |
| E: !! | With such an ECG Signal no QRS complex can be detected. This occurs, for example, when the electrodes of the ECG conduction are open. |
The ECG signal quality information is used for the following actions/displays
- automatic switching off of the ECG display on the overview page
- QRS detection
- optical alarm in case of very poor ECG signal quality
- numeric output in the info block
- as score value
- as a numerical value (which is of a technical nature)
- as a statistical entry in the evaluation display
Setting for the ECG quality display
Settings cann The visibilty of ECG signal quality can be activated in Option 4.13 under Settings → Reha → General → Menu/Functions → Additiona settings for exercise stations → Display options un the exercise.
Description Alert Type bad ECG Signal Quality
During the Rehab Training the ECG signal quality is continuously determined. If the ECG Signal Quality is disrupted, noisy or non-physiological the Software can display a visual Alarm. The Alarm is deactivated by default and can enabled by change the Setting "CSC->cardio concept\training place\EcgQualityAlarmEnabled". If the alarm is activated, a transparent red bar will be displayed in the online ECG on the overview page on the right. It automatically disappears when the ECG Signal Quality has improved.
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In case of a bad ECG signal quality a transparent red square is faded in over the ECG in the online ECG part. With a 3 channel ECG, the rectangle is vertically divided into three equal areas, one for each channel. This allows the quality of all three channels to be signalled simultaneously even if the currently displayed ECG channel is not affected.
Display of ECG signal quality
The ECG quality is dispalyed
- in online ECG view on the owervie page of rehab training
- as score value in any Info block
ECG signal quality dispaly in online ECG view
As long as the ECG has a good quality, no display in online ECG appears on the overview page. In case of insufficient ECG quality, a transparent red rectangle appears on the right side of the online ECG. Depending on the number of ECG channels, either one or three colored rectangles are displayed.
| 1 channel ECG |
| In this case, one ECG channel has a insufficient on quality |
|---|---|---|
| 3 channel ECG |
| In this case the 1st ECG channel is displayed and channels 2 and 3 are of poor quality. |
The display of the ECG quality disappears automatically if this is OK.
Numerical display of ECG quality
In contrast to the graphic quality display, the numerical displays are always retained, even if the ECG is of good quality.
As scrore vlaue
Any information block cann be configured to disaply the ECG quality score value
| 1 channel ECG |
| The ECG channel has a quality score of 6, which means insufficient ECG quality. |
|---|---|---|
| 3 channel ECG |
| In this three-channel ECG display, the ECG channel 1 is of poor quality (score vauel of 6) and the other two channels are not physiological (score value of 20). |
As numerical vaue
The determination of the ECG signal quality has as result a numerical value, which can be interpreted as a measure of the noise. This can be displayed as a single numerical value for each channel. The value itself is more of a technical specification and should therefore only be displayed in disputed quality cases.
| 1 channel ECG |
| The ECG channel has a quality vaue of 5.6 |
|---|---|---|
| 3 channel ECG |
| ECG channel 1 has a quality vaue of 5.6 wich is good ECG, the other channels (value around 14) are are close to the unphysiological signal |
