Luo-Rudy Dynamic Model
for one ventricular cell
This model is used to simulate the activation of ventricular cells using the Luo-Rudy dynamic model.

To use the applet, click the Start button to initiate the simulation and the Reset button to return the parameters to their initial values. Check the box for each variable to plot it in the window.

While the Beeler-Reuter and Luo-Rudy-I applets show so-called "first-generation" ionic models, the Luo-Rudy dynamic (LRd) model is a so-called "second-generation" model that includes formulations of pump and exchanger currents, ionic concentrations, and intracellular calcium dynamics.

BCL indicates the basic cycle length (BCL) or period at which the cell is paced, in ms. Example 1 (default) shows the voltage trace of a 1.2-second simulation of a cell paced at a BCL of 200 ms. Example 2 displays voltage and the gates f, x1, and xr for a cell paced at a BCL of 180ms. The total time simulated is 1000 ms, but only 550 ms are displayed (zoom). Example 3 displays the voltage and calcium concentration [Ca]i for a 2.16 s simulation with a BCL of 90 ms. Example 4 displays the voltage, [Ca]i, [Na]i, and [K]i intracellular ionic concentrations for a 10 s simulation when the cell is paced at a BCL of 150 ms.

Things to try:

  • Uncheck the Voltage box and check the boxes for some of the other variables.
  • Change BCL to analyze rate adaptation and restitution (the last action potential duration is indicated in the lower right corner).
  • After pressing the Plot Currents button, check the Ascii data box to obtain the voltage signal as a function of time. (Note that the larger the signal, the longer it takes for the window to appear.)
  • Zoom in on a particular portion of a simulation by indicating the starting plotting time using the Start Time text filed and the final time using the Final Time text filed. Then press enter or click on the Zoom buton.