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ecgsim -alt TransferFile SourceFile heartFile SurfDistFile VolDistFile ThoraxFile StdLeadsFile LungsFile
with
file | format | description |
TransferFile | matrix | contains the MCG transfer matrix |
SourceFile | matrix | contains initials source parameters |
heartFile | geometry | contains the triangulated heart |
SurfDistFile | matrix | contains the distance between nodes at the heart measured along the surface of the myocardium |
VolDistFile | matrix | contains the distance between nodes at the heart measured through the myocardium |
ThoraxFile | geometry | contains the triangulated torso |
StdLeadsFile | see below | contains |
LungsFile | geometry | contains the triangulated lungs (may be omitted) |
When using the -alt option, you also want to use the -ref option in order to supply an appropriate reference ECG (see below).
Examples of the various files may be downloaded from www.ecgsim.org.
ecgsim -ref ReferenceFile
ReferenceFile is the name of the file containing the reference ECG.
Its format is the standard matrix format (as used
by ECGSIM in saving surface potentials). Each row represents the ECG as a
function of time at the corresponding vertex of the thorax. Consequently, the
number of rows must match the number of vertices of the thorax.
In the unix version you may just type the command line as described above.
In the Windows version you must include the -alt command line option in
a short-cut by which ECGSIM is started. For that purpose, right-click on the short-cut, and
add the -alt option and its parameters to the command line (after
ecgsim.exe). You may want to create a separate short-cut for this
purpose. If you don't give the full path of the files, ECGSIM will look for
them in the "start in" folder defined in the short-cut.
Starting ECGSIM with an alternative reference ECG
In order to start ECGSIM with an alternative reference ECG, you must specify the
file name of the reference ecg in the command line in the following way:
Format of "Standard Leads" files
A "Standard Leads" file must have the following format:
8 | |
1 | v(1) |
2 | v(2) |
. | . |
. | . |
8 | v(8) |
v(1) to v(6) indicate the index of the vertex at the thorax at which v1 to v6 are located. v(7) indicates the vertex to which VR is assigned, and v(8) the vertex to which VL is assigned (usually the tip op the right and left shoulder respectively).
aVR and aVL are constructed by multiplying the potential at v(7) and v(8) by 1.5. aVF is constructed as follows: aVF=-aVR-aVL (note that this assumes the transfer matrix is referenced to Wilson Central Terminal).
The potential at lead I is constructed by taking the potential at v(8) minus the one at v(7). Leads II and III are constructed in a simular fashion.