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Case 3 Triangulated Torso and Heart Geometry

These files, and the notes below, were prepared by A. van Oosterom and P. van Dam. The geometry files are text files. Matlab code for reading and manipulating the .tri files is also provided here.

Geometry (.tri) files: (ascii files)

thorax	case3_torso.tri (370 nodes)
left lung	case3_llung.tri
right lung	case3_rlung.tri
epicardium	case3_peric.tri closed geometry encompassing the ventricles shares nodes with those of the epicardium
ventricles	case3_ventr.tri closed surface bounding ventricular mass: topology: first order doughnut; (because of RVOT) includes: endocardium; epicardium; and connection at the base
left cavity	case3_lendo.tri closed surface representing blood inside cavities shares nodes with those of the endocardium
right cavity	case3_rendo.tri closed surface representing blood inside cavities shares nodes with those of the endocardium

All the above: consistent coordinate system; heart in natural position

• x_axis frontal;
• y_axis: points to the left arm
• z-axis: feet to head direction
• units in mm

left ventricle

case3_LV.tri (corrected) closed surface representing left ventricular myocardium. (right ventricle 'cut off') orientation vertical: along long axis

Auxiliary files

Descriptive trailers are included in these files:

Electrode positions on the thorax	elnodes_123_370.lst ascii file initial row (123 1) specifies matrix size
potential data	ecgs_case3.asc original data as previously posted on PhysioNet (see trailer)

These files are described below:

Load .asc file in Matlab	loadmat.m
Load .tri file in Matlab	loadtri.m
Laplacian interpolator	intripol.m
Save data in .asc form	savemat.m
Save triangulation in .tri form	savetri.m
Sample of ECGs	ecgs_123_leads.jpg
Sample of a BSPM at t=555 ms	bspm_555.jpg
Transfer matrix for interpolation from 123 to 370 nodes	transfer_370_123.mat

Using .tri files in Matlab

Each .tri file can be opened in Matlab as

   [VER,ITRI]=loadtri('filename.tri);

Strip the first column, which contains vertex/triangle labels. VER are coordinates of all nodes of the mesh, and ITRI are ordered triples of the triangles.

The ECG potential data may be imported in Matlab by using:

   PHI=loadmat('ecgs_case3.asc');

After stripping the first 3 columns by:

   PHI=PHI(:,4:355);

Potentials at all 370 nodes representing the thorax can be computed by using the transfer matrix:

    T=loadmat('transfer_370_123.mat');

    PSI=T*PHI;

Finally, the files savemat.m and savetri.m are scripts for storing any similar output data.

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Updated Friday, 28-Sep-2007 21:00:36 EDT