ECGSIM
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Transmembrane Potential (TMP)

The TMP pane displays the transmembrane potential at the selected node on the heart surface (see heart pane). The trace in white relates to the initial parameter values, the one in red relates to the user adapted parameters.
The shape of the TMP can be changed by dragging the parameter handlers. Double clicking on a handler resets the selected parameter to its initial value.

If desired, the resulting electrogram at the selected node may also be displayed by pressing the electrogram button.

For changing the grid type see options/preferences.

The time bar (yellow) indicates a selected time instant, corresponding with the one used in the leads pane. It can be moved by a single left mouse click or dragging.

The image shown in the membrane pane may be copied to the clipboard by selecting Copy from the Membrane menu, or by pressing <Ctrl>-C while the mouse is within the membrane pane.

Changing TMP waveform

Currently, ECGSIM supports 7 parameters to describe the TMP waveform at the selected node:

  • depolarization time, the timing of the fastest upstroke of the TMP.
  • repolarization time, defined as the moment of maximum down-slope during repolarization.
  • resting potential, the minimum TMP, representing the value of the cardiac myocyte at rest.
  • amplitude, the maximum upstroke amplitude.
  • depolarization slope of the the value of the fast upstroke (phase 0).
  • the plateau slope; this is combined with the repolarization slope. It is constrained to be less than or equal to the repolarization slope (approximately phase 2).
  • the repolarization slope, which is combined with the plateau slope. It is constrained to be more than or equal to the plateau slope (approximately phase 3).

For each parameter an initial value exists (indicated in white ), and an user adapted value (indicated in red). The used colors are also used in the leads pane .
The parameters may be changed in groups:

1) the amplitude and timing parameters,
2) the slope parameters.
Double clicking on the parameter handler resets the parameters value to their initial ones.

Undo/Redo

"Undo" and "undo recent changes" may be effected by selecting Undo or Redo from the Edit menu, or by clicking on the Undo/Redo tool button on the tool bar at the top of the membrane pane.

By selecting Undo All, or clicking on the Undo All tool button, all parameters changes for the visible source (atria or ventricles, see heart), made since the start of the program or since the last time a case file was opened, are undone.

Show electrogram

You may use this option in the membrane menu to show or hide the electrogram of the node selected on the heart surface.

Changing adaptation region

This function has three options:
Select a area and use the previously adapted settings to this new selected area. In the previously selected area the adapted parameters are reset to their initial value.
Expand the area and use the previously adapted settings to this new selected area. Previously selected areas are kept at their adapted value.
Adapt the parameters per selected region. None of the parameters are reset.

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