The Modified Luo-Rudy Dynamic Model of the Mammalian Ventricular Myocyte.

Description

 The Luo-Rudy Dynamic (LRd) Model of the Mammalian Ventricular Myocyte. This model describes 
 the mammalian cardiac ventricular action potential in a single cell in guinea pigs. Along 
 with the membrane sodium and potassium currents, the model focuses on processes that regulate 
 intracellular calcium and depend on its concentration. The figure in this section shows all 
 the channels and currents in the modeled single cell.

www.cwru.edu/med/CBRTC/LRdOnline/LRdModel.c. The “C”code 
 was adapted, Illustrative Diagram block for block,into JSIM's Mathematical Modeling Language (MML). 
 The code was substantially 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. “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 structure. Fast equilibria were were replaced by ODE's 
 to avoid solving quadratic and cubic equations–the special innovation of the LR model. Any 
 errors contained in the code are not the fault of the original authors.
	

Figure: This figure is the action potential (thin black line) when stimulated every 300 msec by the stimulus current (thick red line) having duration 1 msec and amplitude 35 uA/cm^2.

Equations

The equations for this model may be viewed by running the JSim model applet and clicking on the Source tab at the bottom left of JSim's Run Time graphical user interface. The equations are written in JSim's Mathematical Modeling Language (MML). See the Introduction to MML and the MML Reference Manual. Additional documentation for MML can be found by using the search option at the Physiome home page.