Spatiotemporal correlation uncovers characteristic lengths in cardiac tissue
Spatiotemporal correlation uncovers characteristic lengths in cardiac tissue
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DOI：
10.1103/physreve.100.020201
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发表时间：
2019-08-16
影响因子：
2.4
通讯作者：
Filippi, Simonetta
中科院分区：
文献类型：
--
作者：
Loppini, Alessandro;Gizzi, Alessio;Filippi, Simonetta
动作电位持续时间的复杂时空模式已被证明在许多哺乳动物心脏中发生，这是由于随着刺激频率的增加而发展的倍周期分叉。在这里，我们通过高分辨率光学标测实验和数学建模，通过时空相关性分析，在不同的刺激频率和纤颤过程中，引入了犬心室楔形区心脏活动的特征空间长度。我们发现，在一对一的响应过程中，特征长度从40到20厘米不等，在从倍周期分叉到纤颤的转变过程中，特征长度减小到约3厘米。我们进一步证明，在原纤化过程中，特征长度约为1厘米。我们分析的另一个重要结果是通过对实验数据的非线性拟合得到了本构唯象定律，该定律将传导速度恢复曲线与系统的特征长度联系起来。我们的唯象定律中3/2的分数指数与通过精确的数学模型在真实心脏区域内再现实验纤颤动力学所需的区域大小重新映射是一致的。
Complex spatiotemporal patterns of action potential duration have been shown to occur in many mammalian hearts due to period-doubling bifurcations that develop with increasing frequency of stimulation. Here, through high-resolution optical mapping experiments and mathematical modeling, we introduce a characteristic spatial length of cardiac activity in canine ventricular wedges via a spatiotemporal correlation analysis, at different stimulation frequencies and during fibrillation. We show that the characteristic length ranges from 40 to 20 cm during one-to-one responses and it decreases to a specific value of about 3 cm at the transition from period-doubling bifurcation to fibrillation. We further show that during fibrillation, the characteristic length is about 1 cm. Another significant outcome of our analysis is the finding of a constitutive phenomenological law obtained from a nonlinear fitting of experimental data which relates the conduction velocity restitution curve with the characteristic length of the system. The fractional exponent of 3/2 in our phenomenological law is in agreement with the domain size remapping required to reproduce experimental fibrillation dynamics within a realistic cardiac domain via accurate mathematical models.