MLRd: Modified Luo-Rudy dynamic model of the guinea pig cardiac ventricular action potential in a single cell

1. TABLE OF CONTENTS

References:

How coded:

The JSim code for the Modified Luo-Rudy dynamic model

The JSim model parameters for the stimulus (st) for the model:

Model demonstrations with parameter sets:

2. IMPORTANT !!! To run a demonstration, enter "xhost +" in one of your windows to allow the demonstration program to open windows on your machine !!!

3. References

Detailed list of references are provided in

http://www.cwru.edu/med/CBRTC/LRdOnline/LRdModel.c

and

http://www.cwru.edu/med/CBRTC/LRdOnline/refs.htm

4. How coded:

This is a JSIM adaptation of Gregory M. Faber's C-code detailed below. The JSim code has been processed to run under the XSIM interface. The C-code has been modified, converting many of the expressions into ordinary differential equations. Rapid equilibria have been transformed into "fast" ODE's in order to avoid iterative procedures, complex polynomial solutions, etc. This adaptation was done by Gary M. Raymond December 12, 2001. Original "C" code was from

http://www.cwru.edu/med/CBRTC/LRdOnline/LRdModel.c.

Technique: C-code was basically adapted, block for block. C subroutines for currents were converted to ordinary differential equations where necessary. Stimulus was replaced by JSIM's external function (extern real st(t);). Information pertaining to step size was removed and replaced by JSIM's realDomain t. Recording of maximum excursions on a beat by beat basis was deleted. Double declarations (C construct) were replaced by real declarations (JSIM's MML construct which are double precision variables.) The C subroutines were converted to inline code and placed earlier in the model. Fast equilibria were were replaced by ODE's to avoid solving quadratic and cubic equations--the special innovation of the LR model.

Minor modifications were made in the code combining many variables, e.g. R*Temp/F has become the quantity RTOF (meaning R*T over F). The reciprocal of this quantity is FORT (meaning F over R*T). A four state model was incorporated to model Irelcicr replacing the formulation given in the Luo-Rudy model.

5. The JSim code for the Modified Luo-Rudy dynamic model

MLRd.mod

6. The JSim model parameters for the stimulus (st) for the model

XSIM Function Generator: Square wave pulse train

Offset: 0

Start time: 25

Duration: 10000

Amplitude: 35

Frequency: 0.00333333

Phase Lag: 0

Shape factor: 0.00333333

 

JSim Function Generator: Pulse1

startTime: 25

duration: 1

amplitude: 35

offset: 0

timeToRepeat: 300

7. Model demonstrations with parameter sets

The user should inspect the input parameters and the output curves. Output curves can be found under the Results button under Plot Area 1.

The following parameter set can be demonstrated by clicking on MLRd.par.

Run the model. Under Results, display Plot Area 1. This parameter sets reproduces a sequence of action potentials.

 


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Contact garyr@nsr.bioeng.washington.edu with comments, questions, or critiques.