离散可激发介质激发性降低的几种起因

Some origins of the low excitability of a discrete excitable medium

采用简单的可激发介质元胞自动机模型,通过在均匀介质中引入死亡细胞、疲劳细胞以及让元胞的激发阈值作周期变化使螺旋波漫游.通过监测元胞的激发比率,发现不同原因导致的螺旋波漫游有一个共同的特点:螺旋波漫游情况下的元胞的激发比率较螺旋波不漫游情况下的元胞激发比率减小许多,表明介质的激发性降低与死亡细胞、疲劳细胞的数量以及元胞的激发阈值作周期变化有关;研究结果还表明:介质激发性的降低始终伴随螺旋波频率的减小.这些结果对心脏病的预防与治疗可能会提供有益的帮助.

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.