This article describes how to activate the optional setting of the ECG quality display and how the system display the current ECG quality.
In rehab, the ECG signal is evaluated for its quality. The program analyses the signal quality separately for each ECG channel 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
The visibilty of ECG signal quality can be activated in Option 4.13 under Settings → Reha → General → Menu/Functions → Additional settings for exercise stations → Display options in the exercise.
In case of a bad ECG signal quality a transparent red square is fade 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.
The ECG quality is dispalyed
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.
In contrast to the graphic quality display, the numerical displays are always retained, even if the ECG is of good quality.
Any information block can be configured to display 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). |
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 close to the unphysiological signal |
