I have been developing cardiac simulation, which is now called CARPentry, for over 20 years. Free binary versions for Linux and Macs are available for download.
I have, in parallel, created a visualization tool called meshalyzer for displaying 3D finite element meshes and dispaying time dependent data sets on them. It has a lot of features and can be used to produce nice looking movies. All images of my research were produced with it.
I like the plotting program grace but find it so much more useable after installing the patch that I maintain. Get the source, apply the patch, recompile and discover a pretty decent plotting and analysis program.