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，航天中体液［Ｃａ＋＋］ｏ的变化是引起心脏起搏细胞兴奋节律改变及其心律失常的不可忽视的因素 Objective To investigate the effect of changes of [Ca ++] o on the rhythm of heartbeat in space fluid electrolyte. Methods The peak-to-peak interphase (ISI) of action potential of cardiac cells was studied by using Chay model, which is the smallest excitatory cell ion channel, and the parameter Vc (related to [Ca ++] o) Observed changes in ISI. Results The phenomenon of periodic motion, chaotic motion and bifurcation of periodic and doubling cycles in ISI indicated that the change of [Ca ++] o in space could cause the change of excitatory rhythm of cardiac pacemaker cells, and then change the rhythm of heart beating accordingly. Conclusions In addition to the role of neural and humoral regulatory factors in cardiac activity, the changes of [Ca ++] o in the body fluids of aerospace are not negligible factors that cause excitatory rhythm changes and arrhythmia in cardiac pacemaker cells