除颤波形对细胞动作电位影响的模型研究

Model Reseach of Effects of Defibrillation Waveform on Action Potential Duration.

目的研究除颤中双相波优于单相波的理论依据。方法调整Luo-Rudy模型使其满足除颤研究的需要,研究不同除颤波形对单细胞动作电位的影响。结果双相电场脉冲比单相脉冲更多地扩展细胞的动作电位时程;不同强度的双相波电场脉冲,对动作电位时程的扩展能力非常相近,而不同强度的单相波对动作电位的扩展能力差别很大,电击后动作电位时程空间分布不均匀;动作电位的扩展主要取决于脉冲强度的峰值,和脉冲持续时间关系不大。结论临床上双相波形具有更好的除颤效果,除了其更强的动作电位时程扩展能力外,更多的可能是由于双相波电击后心肌组织中动作电位时程的空间均匀性分布,减少了再次诱发新室颤的几率。

Objective To explore the mechanism underlying the superiority of the biphasic waveform to monophasic waveform in defibrillation. Method The Luo-Rudy model was adjusted so that it could be used to study defibrillation. Based on the adjusted model the effects of different defibrillation waveforms on cell action potential duration （APD） were studied. Result Biphasic electrical field pulse extended the APD longer than that with monophasic one. Moreover, biphasic waveforms with different strengths could prolong the APD almost equally, while monophasic pulses with different strengths showed different ability to prolong the APD and the spatial distribution of the APD became dispersed. It was also found that the strength of electrical fields pulse contributed much to the change of APD while the duration showed little effect. Conclusion The clinical superiority of biphasic pulses to monophasic pulses in defibrillation is resulted from its ability to prolong the time course of the APD and more importantly, it causes even spatial distribution of the APD.