Want to know about the files e.g. plv.dat, CORONARY_PARAMS.dat, scaled_pulse_flow.flow in Coronary Normal?

[Sajeda Akter]

Hi everyone!!
I am a new Simvascular user. Currently, I am running a project that coronary blood simulation. I think Simvascular is simply the best. I created LMA model and generated mesh. In the simulation step, I saw some files in Coronary Normal test e.g. plv.dat, CORONARY_PARAMS.dat, scaled_pulse_flow.flow. In this regards, I want to know what types of these files? How can I create for my own models and simulation? ...Thanks

[Justin Tran]

Hi Sajeda,

Thank you for giving SimVascular a try! We are always happy to welcome new users. The files you mentioned are used in setting the inflow and outflow boundary conditions for the coronary simulation. I will explain the files below, referring to the Coronary Normal Tutorial here: http://simvascular.github.io/clinicalCase3.html as "the tutorial". In short, these are files which provide some nice "default" settings for the boundary conditions for a coronary model. We recommend you try a simulation with these first, then adjust their values after you see the results.

plv.dat - This file contains a left ventricular pressure wave vs. time. If you open the file in a text editor, you should notice 2 columns. The first column is time (it goes from 0.0 to 1.0 since we assume that this patient has a heart rate of 60 bpm), and the second column is pressure at those times in dyne/cm^2 (the cgs unit for pressure). This is used to set the intramyocardial pressure. If you look at Figure 12 in the tutorial, you should notice that there is a pressure generator source connected to the capacity Cim. This is the intramyocardial pressure. This is to model the fact that the coronary vessels exhibit increased resistance during systole, thus impeding flow. Since the coronary vessels rest on the walls of the heart, they get "squeezed" whenever the heart contracts during systole. This pressure source term (which is modeled as the left ventricular pressure) has high pressure in systole, thus impeding flow. This helps our simulations get the desired physiologic flow waveform, as shown in Figures 17 and 18.

CORONARY_PARAMS.dat - These are settings for the overall values of the resistance, capacitance, and intramyocardial pressure scaling for the coronary outlets. Their explanations are outlined in the section "Selection of Parameter Values". If you are running a simulation for the first time, we recommend using these values right out of the box and seeing how the simulation results come out. If the results do not match what you expect, you can tweak these parameters. Explanations for how to do so are outlined in the tutorial.

scaled_pulse_flow.flow - This specifies the flow vs. time boundary condition at the inlet. Similar to plv.dat, this file is in a 2 column format: the first column being time and the second column being flow. This curve was set to match a physiologic flow waveform in the aorta.

Hope these help! Again, for your first simulation we recommend using these files right out of the box and adjusting them after observing the results. Let us know how the simulation goes!

[Sajeda Akter]

Thank you very much Justin Tran for your impressive reply. I hope it will be helpful and I will inform you about my progress later...thanks again