Cabo C, Barr R C
Department of Biomedical Engineering, Duke University, Durham, NC 27706.
Med Biol Eng Comput. 1992 May;30(3):292-302. doi: 10.1007/BF02446967.
Propagation, re-entry and the effects of stimuli within the conduction system can be studied effectively with computer models when the pertinent membrane properties can be represented accurately in mathematical form. To date, no membrane models have been shown to be accurate representations during repolarisation and recovery of excitability, although for the Purkinje membrane the DiFrancesco-Noble (DN) model has become a possibility. The paper examines the DN model, restates its equations and compares simulated waveforms in a number of propagation contexts to experimental measurements reported in the literature. The objective is to determine whether or not the DN model reproduced phenomena such as supernormality, shortening in action potential duration during pacing rate increases, alternation of duration with changes in rhythm, graded responses and 'all-or-none' repolarisation in a quantitatively realistic way, as each of these come from time and space dependencies not directly a part of the ionic current measurements on which the DN model is based. The results show that the DN equations correctly simulate these situations and support the goal of having a model that is broadly applicable to Purkinje tissue, including refractory period properties and response to electrical stimulation.
当相关的膜特性能够以数学形式准确表示时，利用计算机模型可以有效地研究传导系统内的传播、折返以及刺激的影响。迄今为止，尽管对于浦肯野膜来说，迪弗朗切斯科 - 诺布尔（DN）模型已成为一种可能，但尚未有膜模型在复极化和兴奋性恢复过程中被证明是准确的表示。本文研究了DN模型，重新阐述了其方程，并在多种传播情况下将模拟波形与文献中报道的实验测量结果进行了比较。目的是确定DN模型是否以定量现实的方式再现了诸如超常期、起搏频率增加时动作电位持续时间缩短、节律变化时持续时间的交替、分级反应以及“全或无”复极化等现象，因为这些现象均源于时间和空间依赖性，而并非直接是DN模型所基于的离子电流测量的一部分。结果表明，DN方程能够正确模拟这些情况，并支持构建一个广泛适用于浦肯野组织的模型这一目标，该模型包括不应期特性和对电刺激的反应。
