Some origins of the low excitability of a discrete excitable medium

Abstract

The simple model of discrete excitable medium is applied. In order to make spiral wave meander，we introduce some death cells and fatigue cells into a homogeneous medium，respectively，or periodically change the excitation threshold of cells. By monitoring the fraction of excitation cells，we find that there is a remarkable common feature for spiral wave meandering induced by different factors，i.e.，the fraction of excitation cells under spiral wave meandering is smaller than that under stable spiral wave，which indicates that the low excitability of a medium is related to the number of death cells and fatigue cells in the medium，and the periodical change of the excitation threshold of cells，respectively. The numerical results show that the decrease of the excitability of media always accompanies the decrease of the frequency of spiral wave. We hope the present work can provide help for medical workers on the prevention and treatment of heart disease.