Thorax
The thorax pane is used to display the geometry of the thorax, and any of a wide
range of functions on the thorax surface. If a node on the thorax is selected,
it is shown by a black patch on the surface.
What exactly is displayed in the thorax pane and how, is controlled by the
various menu options
available from the Thorax entry on the menu bar:
Mouse actions in the thorax pane are reflected
in this pane and may also have an effect on the other ones.
The contents of the thorax pane is copied onto the
clipboard by selecting Copy from the Thorax menu, or by
pressing Ctrl-C while the mouse is within the thorax pane.
Surface function
The item Surface function in the thorax menu brings up a
dialog window, with which you may choose the function to be displayed
on the thorax surface.
Available are the simulated potentials (i.e. the potentials that result from
the transmembrane potentials at the heart as set by the user), the reference
(i.e. measured) potentials, 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 thorax pane.
If surface potentials are displayed in the thorax pane, 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 the time by steps
of milliseconds. Use the page up and page down keys for in- and decrements with
steps of ten milliseconds. Also, you may click in the membrane or in the
ECGs pane to select the
time instant for which you wish the potentials to be displayed. Finally, you
may use the movie option to view the development
of the potentials in time as a movie.
Display options
The item Display options in the Thorax menu brings up a
dialog window, from which you may select how the thorax and the surface function are
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
In the Geometry tab you may determine whether you want the
heart, lungs, thorax and precordial electrodes to be displayed,
and whether you want them to be transparent or opaque.
If a function is mapped on
the thorax using a color code, the surface will always remain opaque, as a
colored transparent thorax is too confusing. If you want to map a function on the
thorax 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 20 cm/mV times the scale factor of the signals in the ECGs pane. Change the size of the displayed vector by
changing the scale in the ECGs pane.
Also, you may choose whether the grid and/or
the nodes that make up the discretized thorax are to 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 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 thorax,
but it also renders the colors on the surface less bright.
Scale
The item Scale in the thorax menu brings up a
dialog window, by which you set the scale for the various surface functions that can
be plotted on the thorax surface. This dialog window may also be started by clicking
on the Scale button on the thorax tool bar.
Mouse actions in the thorax pane
Orientation
You may rotate the thorax by left-mouse dragging, i.e. move the mouse while
holding the left mouse button down. By rotating the mouse wheel, the thorax
rotates along an axis perpendicular to the screen.
If you press the shift key
simultaneously, the angle by which the thorax rotates with each click of the mouse
wheel becomes smaller.
You may go back to
the standard frontal view by clicking on the reset orientation button
on the tool bar.
A node at the thorax is selected by clicking with the right mouse button on the
thorax 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 thorax, the currently selected node is deselected.
If a function is mapped on the thorax surface, the value at the
selected node is displayed on the status bar of the thorax pane. If the geometry
is displayed, the index of the selected node is displayed
(the node index corresponds to the row in which the surface potentials for that
node are saved).
In the ECGs pane you may choose to
display just the (single) ECG at the selected node.
