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Electrocardiography (ECG)


Prepare and select a study folder as described in analysis settings and study folder.

ECG analysis

Click on the "open data file" button and select a raw data file to analyze. You will be prompted with the import signals dialog to select the proper ECG signal from your datafile. On this dialog first you need to specify wether you wish to load all available data in the file or a subsection. You can either select to load a certain time range, or load a predefined segment.  (see analysis procedure, data import and timing files). Second, select the proper ECG channel for analysis and any additional channels for display you need to edit the data (e.g. marker/trigger information or accelerometer for artefact identification). Click ok, and wait for EMEGS to load the data.

1. R-wave

The first step performed in the ECG analysis is the R-wave detection, which is done with a simple rise criterion and a refractory period.. You are prompted with a dialog to configure the R-wave detection process if necessary. You can differntiate or invert the signal, adjust size and position of the sample window, change height and with of the rise criterion and the lenght of the refractory period. When you are done, hit to Ok button to have EMEGS identify R-waves with the selected settings.


EMEGS will write a message on the low window to indicate how many R-waves are found.

Then the instantaneous interbeat interval is calculated and displayed below the ECG raw signal for editing of false positive R-waves or misses

You can edit the IBI signal by adding, removing and dragging R-waves in the ECG trace - the IBI trace is updated accordingly. Also you can use the connect/exclude functions directly on the IBI signal. In the latter case EMEGS will try to set R-wave markers automatically according to your editing.

Moving the mouse over R-wave markers, the mouse cursor changes to a left-right arrow, allowing you  to drag them left or right. When over an R-wave marker, you can also select   Delete from the context menu to remove the R-wave marker. Select Insert from the context menu when not over an existing R-wave marker to insert a new R-wave marker at the mouse position. To insert an additional R-wave marker between two beats select Insert at 50% from the context menu, to insert 2 markers select Insert at 33% and 66%.

In order to fill gaps of unrecognized R-waves, it is sometimes helpful to continue the current IBI from the borders of a gap as an estimate for the expected R-wave position. You can extrapolate IBI-values in this way from the left or the right side using the Continue to the right and the Continue to the left command from the context menu.

You can undo all editing step using the history docking widget, by using the undo/redo button on the editing toolbar or using the keyboard shortcuts Strg+Z and Strg+Y.

2. P-,Q-, S- and T-wave

When done editing the R-waves, proceed by clicking the Resume analysis button. A dialog will open to allow you to configure the detection of the remaining ECG-components: P-, Q-, S- and T-wave.

Although these waves are detected by their maximum amplitude, it is mostly the onset (or the offset) of these waves that is of further interest. The onset (or offset) is however often difficult to find, especially in a noisy signal, which is why EMEGS can set the onset/offset at a fixed distance from the maximum (P- and Q-wave) or find the baseline-crossing of a tangent at the steepest slope point (T-wave) as an alternative. Configure the detection to best match your data, then click OK.

EMEGS will analyze all beats in  your data file, calculate T-wave amplitude, the QT-interval and the PQ-interval and display them for editing.

When you zoom in close enough, the corresponding line markers are displayed and can be edited similarly to the R-wave editing in the first step. Note that editing of the R-waves must be completed first and cannot be changed while editing the other components.

Value export