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The heart pane is used to display the geometry of the heart and any of a wide range of functions on its surface. If a node on the heart is selected by right a mouse button click, its position is shown by a black patch.

The function that is being displayed in the heart pane, as well as various display options that can be be selected from the Heart entry on the menu bar:

Mouse actions in the heart pane are reflected in this pane and may also have an effect on the other ones.

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

Surface function

The item Surface function in the heart menu brings up a dialog window, with which you may choose the function to be displayed on the heart surface. Options available are: the depolarization times, repolarization times, action potential duration, action potential magnitude, transmembrane potential, epicardial potential and the transfer function.

The most frequently used surface functions may also be activated by clicking on the corresponding button on the tool bar at the top of the heart pane.

If transmembrane or epicardial potentials are displayed, the status bar indicates the time instant for which the potentials are displayed. You may press the up and down arrow keys to in- and decrease time by steps of one millisecond. Use the page up and page down keys for in- and decrements with steps of ten milliseconds. Also, you may click in the membrane and ECGs pane on the time instant for which you wish the potentials to be displayed. Finally, you may use the movie option to view the development in time of the potentials as a movie.

Display options

The item Display options in the Heart menu brings up a dialog window in which you may choose how the heart and the surface function are to be displayed. There are two tabs: the Geometry tab that controls the geometry options, and the Surface function tab that controls the surface function options.

Display options: Geometry

To facilitate orientation, the left arteria decendens marking the boundary between the right and left ventricle may be brought into view. In addition, the precordial thoracic electrodes may be included in the display. In the geometry tab you may select whether you want the electrodes to be shown, and whether you want them to be transparent or opaque.

You may choose whether the size of the range around the selected node that is affected by changes of the source parameters at the selected node (see range) should be shown on the heart surface. You may choose to display the outline of the range, to dim the region of the heart surface that is within the range, or to dim the region outside the range. You may also turn the range display on and off by using the range on/off button on the heart tool bar. The size of the range may be controlled by using the mouse.

The heart surface may be hidden or made transparent. If a function is mapped on the heart surface using a color code, the surface will always be opaque, since a colored transparent heart is too confusing. Should you want to map a function on the heart while being able to see through the surface, use isofunction lines only.

The heart vector and vector loop (according to the Frank Leads) for the simulated data may be displayed by choosing opaque for the corresponding items. The scale of the vector is 13 cm/mV times the scale factor of the signals in the ECGs pane. You may change the size of the displayed vector by using the scale in the ECGs pane.

Finally, you may select in the geometry tab whether the grid and/or the nodes that make up the discretized heart should be displayed.

Display options: Surface function

The surface function tab allows you to determine how the function is displayed; by a color map, isofunction lines, or by both. Also, you may determine whether the light effect should be active when using a color map display. The light effect gives a three-dimensional impression of the geometry of the heart, but it also renders the colors on the surface less bright.


The item Scale in the heart menu brings up a dialog window, through which you may set the scale for the various surface functions that are plotted on the heart surface.

By default, the scale of time functions (repolarization, depolarization and action potential duration) is adapted automatically as the timing values change. By unchecking the Autoscale check box, manual control by means of the three timing sliders is enabled.

Mouse actions in the heart pane


You may rotate the heart by (left) mouse dragging. By rotating the mouse wheel, the heart rotates along an axis perpendicular to the screen. If you press the shift key simultaneously, the angle by which the heart rotates with each click of the mouse wheel becomes smaller.

You may easily return to the standard frontal view by clicking on the reset orientation button on the tool bar.


A node at the heart is selected by a right mouse button click on the heart surface. The node nearest to the "click" is selected, as shown by a black patch on the surface. Only one node may be selected at a time; if you select another node, the previous one is deselected. If you click on the right mouse button outside the heart, the currently selected node is deselected.

If a function is mapped on the heart surface, the value at the selected node is displayed on the status bar of the heart pane. If the geometry is displayed, the location of the selected node and its index are displayed (the node index corresponds to the row in which the source parameters for that node are saved).

In the membrane pane the transmembrane potential of the selected node is displayed.

Setting the range

The size of the range around the selected node that is affected by changes of the source parameters at the selected node (see range) may be set by clicking the middle mouse button. The point that was clicked on will define the edge of the selected range. If your mouse does not have a middle button, or if a special function has been assigned to the middle mouse button by the mouse driver (as is often the case in Windows), you may get the same result by clicking with the right mouse button, while holding down the shift key.

The size of the range may also be set from the range dialog window in the membrane menu. In this dialog window you may also choose whether the range should be computed through the myocardium (transmuraly), or merely on the part of the heart surface that carries the selected node.