体液[Ca^(++)]_o变化诱发的心脏起搏细胞兴奋节律的分叉与混沌(Chay模型)

Bifurcation and Chaos of Heart Cell Pacing Rhythm Evoked by Changing +]o in Body Fluid.

目的探讨航天中体液电解质中［Ｃａ＋＋］ｏ变化对心跳节律的影响。方法应用可兴奋性细胞离子通道最小模型—柴（Ｃｈａｙ）模型，以心脏细胞动作电位峰－峰间期（ＩＳＩ）为研究对象，调节方程中的参数Ｖｃ，（与［Ｃａ＋＋］ｏ有关），观察ＩＳＩ的变化。结果ＩＳＩ出现周期运动、混沌运动及加周期、倍周期分叉等现象，表明航天中［Ｃａ＋＋］ｏ变化可能会引起心脏起搏细胞兴奋节律的变化，并进而使心跳节律发生相应变化。结论除心脏活动的神经、体液调节因素作用以外。

Objective To study the effect of changes of electrolyte concentration on heart cell pacing rhythm. Method The minimal model of gating mechanism for ionic channels of exciting cells was used in this study.ISI(interspike interval) is regarded as the key parameter. Result ISI appears period, chaos, period adding bifurcation and period doubling bifurcation when Vc, a parameter related to o,was adjusted. Conclusion The results reveal that changes of o may evoke changes of rhythm of heart pacemaker cells. This implies that changes of o of body fluid are a cause influencing pacing rhythm of pacemaker cells and cardiac arrhythmia besides the neurohumoral regulation,which should not be ignored.