Session S23.1

Adaptation of a Minimal Four-State Cell Model for Reproducing Atrial Excitation Properties

FM Weber*, S Lurz, DUJ Keller, DL Weiss,
G Seemann, C Lorenz, O Dössel

Universität Karlsruhe
Karlsruhe, Germany

Simulation of cardiac excitation is most often a trade-off between accuracy and simulation speed. While detailed, but time-consuming, ionic cell models reflect reality quite accurately, alternative approaches such as a cellular automaton are faster but suffer from discretization effects. A minimal model with four state variables has recently been presented by Fenton and co-workers with parameterization for reproducing ventricular action potentials. While still using Hodgkin-Huxley type equations, it is a lot faster and could therefore be an alternative to much more discrete automaton systems.
In this contribution, we have fitted the parameters of the four-state model such that it can reproduce atrial action potentials. Fitting is performed using a particle swarm algorithm with reference action potential curves generated using the Courtemanche model. Reproduction of APD restitution is also considered in the fitting process.
Model properties in tissue are investigated in a quasi one-dimensional patch. We further demonstrate the simulation of a sinus beat on the atria in a realistic 3D geometry using the fitted four-state model in a monodomain simulation. The total simulation time for one heart-beat (1s) was approximately 90 minutes. The result is compared with a simulation of atrial depolarization using the Courtemanche reference model.

(Abstract Control Number: 122)