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If the source parameters loaded from a file contain depolarization times beyond 500 ms, the maximum repolarization time is automatically set to 1000 ms.
The number of rows in the file must match the number of nodes on the thorax. See surface potential files for the file format.
Reference surface potentials may also be loaded when ECGSIM starts by using the -ref command line option.
ECGSIM sends a bitmap copy of the pane to the printer, hence the resolution of the print-out is that of the screen and not that of the printer (which commonly has a much higher resolution). You may improve the quality of the print-out by enlarging the pane you want to print, which is done by dragging the bars between the pane by the left mouse button.
We plan to make use of the full printer resolution in a later release of ECGSIM.
where N is the number of rows that follow (=the number of nodes at the heart; N=257 for the default heart geometry), 3 is the number of columns, d(n) is the depolarization time at node n in ms, r(n) is the repolarization time at node n in ms, and s(n) is the depolarization magnitude at node n. The scaling of the latter ranges from a value of 0 for inactive nodes to 1 for the full (relative) magnitude of the upstroke of the transmembrane potential.
The index n of a selected heart node may be displayed on the status bar of the heart pane by displaying the geometry in that pane and selecting the node.
The geometry description of the heart may be downloaded from www.ecgsim.org.
The format of the file is the standard format used for matrix files in ECGSIM:
where L is the number of rows that follow (=the number of nodes on the thorax; L=300 for the default torso geometry), T is the number of columns (=number of time samples) and p(l,t) is the potential in mV at node l at sampling time t.
The sample frequency is 1000 Hz.
The index of the selected thorax node may be displayed on the status bar of the thorax pane by displaying the geometry in that pane and selecting the node.
The geometry description of the thorax may downloaded from www.ecgsim.org.
where L is the number of rows that follow (=the number of leads, normally 12), T is the number of columns (=number of time samples) and p(l,t) is the potential in mV at lead l at time sample t.
Rows 1-6 correspond to leads V1-V6, rows 7-9 to leads aVR, aVL and aVF, respectively and rows 10-12 to leads I, II and III, respectively.
The implied sample frequency is 1000 Hz.
The format of the files that describe triangulated geometries is as follows:
where npnt is the number of vertices, x(i), y(i) and z(i) are the coordinates (in meters) of vertex i, ntri is the number of triangles, and ind(j,1), ind(j,2) and ind(j,3) are the indices of the vertices of triangle j. The order of the indices for a triangle defines the orientation of the triangle; when viewed from the outside the vertices are numbered clockwise.