Background

Precise analysis of cardiac spiral wave (SW) dynamics is essential for effective arrhythmia treatment. Although the phase singularity (PS) point in the spatial phase map has been used to determine the cardiac SW center for decades, quantitative detection algorithms that assume PS as a point fail to trace complex and rapid PS dynamics. Through a detailed analysis of numerical simulations, we examined our hypothesis that a boundary of spatial phase discontinuity induced by a focal conduction block exists around the moving SW center in the phase map.

Method

In a numerical simulation model of a 2D cardiac sheet, three different types of SWs (short wavelength; long wavelength; and low excitability) were induced by regulating ion channels. Discontinuities of all boundaries among adjacent cells at each instance were evaluated by calculating the phase bipolarity (PB). The total amount of phase transition (PTA) in each cell during the study period was evaluated.

Results

Pivoting, drifting, and shifting SWs were observed in the short-wavelength, low-excitability, and long-wavelength models, respectively. For both the drifting and shifting cases, long high-PB edges were observed on the SW trajectories. In all cases, the conduction block (CB) was observed at the same boundaries. These were also identical to the boundaries in the PTA maps.

Conclusions

The analysis of the simulations revealed that the conduction block at the center of a moving SW induces discontinuous boundaries in spatial phase maps that represent a more appropriate model of the SW center than the PS point.

中文翻译：

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在移动的心脏螺旋波中心的空间相位不连续性

背景

精确分析心脏螺旋波（SW）动力学对于有效的心律失常治疗至关重要。尽管空间相位图中的相位奇异点（PS）已被用于确定心脏SW中心数十年，但以PS为点的定量检测算法无法追踪复杂而快速的PS动态。通过对数值模拟的详细分析，我们检验了以下假设：在相位图中，由焦点传导块引起的空间相位不连续性边界存在于运动的SW中心周围。

方法

在二维心脏片材的数值模拟模型中，通过调节离子通道诱导了三种不同类型的SW（短波长；长波长；和低兴奋性）。通过计算相双极性（PB）来评估每种情况下相邻单元之间所有边界的不连续性。评估研究期间每个电池中的相变（PTA）总量。

结果

在短波长，低激发性和长波长模型中分别观察到了SW的旋转，漂移和移动。对于漂移和漂移情况，在SW轨迹上都观察到了较长的高PB边缘。在所有情况下，都在相同边界处观察到传导阻滞（CB）。这些也与PTA地图中的边界相同。

结论

对模拟的分析表明，在移动的SW中心处的传导块会在空间相位图中诱发不连续的边界，这代表了比PS点更合适的SW中心模型。