Joint seminars: Multiplicative Stochastic Processes for Characterizing Ventricular Fibrillation in 2D Beeler-Reuter Model (Hidetoshi Konno, Tsukuba, Sep.21, 2012)

Joint seminars 32

Title: Multiplicative Stochastic Processes for Characterizing Ventricular Fibrillation in 2D Beeler-Reuter Model

Speaker: Hidetoshi Konno (INPAC), Tsukuba University

Location: 601 Pao Yue-Kong Library

Time: 2:00pm-3:00pm, Sep 21 (Friday)

Abstract:

Large multiple-scale computer simulations of virtual hearts have been performed in many research laboratories (i) to understand the mechanism of heart diseases; and (ii) to utilize these cardiac models in drug development. In spite of the extensive studies, there are many fundamental dynamical features that are not clarified even in a simple ion-channel based cardiac model.

We have studied a state of ventricular fibrillation (VF) in a modified 2D Beerler-Reuter model (BR) from the viewpoint of nonlinear stochastic processes associated with the simple ion-channel model. The state of VF is characterized by the annihilation and creation of broken pieces of spiral waves. We firstly studied stochastic processes of the number of phase-singularity N(t) in the VF. It is found that N(t) can be identified by the Hyper-Gamma process under the influence of a multiplicative noise [1]. Then, we have examined the predator-prey variables [2] and construct a stochastic predator-prey model under the influence of multiplicative noises [3]. It is shown that the model can catch the dynamical features of the predator-prey variables in a VF state in the BR model.