Faculty of Medicine, The University of Tokyo , Tokyo , Japan.
Department of Engineering, The University of Tokyo , Tokyo , Japan.
Am J Physiol Heart Circ Physiol. 2018 Aug 1;315(2):H318-H326. doi: 10.1152/ajpheart.00558.2017. Epub 2018 Mar 9.
The action mechanism of stimulation toward spiral waves (SWs) owing to the complex excitation patterns that occur just after point stimulation has not yet been experimentally clarified. This study sought to test our hypothesis that the effect of capturing excitable gap of SWs by stimulation can also be explained as the interaction of original phase singularity (PS) and PSs induced by the stimulation on the wave tail (WT) of the original SW. Phase variance analysis was used to quantitatively analyze the postshock PS trajectories. In a two-dimensional subepicardial layer of Langendorff-perfused rabbit hearts, optical mapping was used to record the excitation pattern during stimulation. After a SW was induced by S1-S2 shock, single biphasic point stimulation S3 was applied. In 70 of the S1-S2-S3 stimulation episodes applied on 6 hearts, the original PS was clearly observed just before the S3 point stimulation in 37 episodes. Pairwise PSs were newly induced by the S3 in 20 episodes. The original PS collided with the newly induced PSs in 16 episodes; otherwise, they did not interact with the original PS. SW shift occurred most efficiently when the S3 shock was applied at the relative refractory period, and PS shifted in the direction of the WT. In conclusion, quantitative tracking of PS clarified that stimulation in desirable conditions induces pairwise PSs on WT and that the collision of PSs causes SW shift along the WT. The results of this study indicate the importance of the interaction of shock-induced excitation with the WT for effective stimulation. NEW & NOTEWORTHY The quantitative analysis of spiral wave dynamics during stimulation clarified the action mechanism of capturing the excitable gap, i.e., the induction of pairwise phase singularities on the wave tail and spiral wave shift along the wave tail as a result of these interactions. The importance of the wave tail for effective stimulation was revealed.
刺激螺旋波（SW）的作用机制，由于刺激后立即出现的复杂兴奋模式，尚未通过实验得到明确证实。本研究旨在验证我们的假设，即刺激捕获 SW 可兴奋间隙的效果也可以解释为刺激对原始 SW 波尾（WT）上的原始相位奇点（PS）和 PS 诱导的相互作用。相位方差分析用于定量分析冲击后 PS 轨迹。在 Langendorff 灌注兔心的二维心外膜层中，使用光学映射记录刺激期间的兴奋模式。在 S1-S2 冲击诱导 SW 后，应用单相双相点刺激 S3。在对 6 个心脏应用的 70 个 S1-S2-S3 刺激发作中，在 37 个发作中，在 S3 点刺激之前清楚地观察到原始 PS。在 20 个发作中，S3 新诱导了成对 PS。在 16 个发作中，原始 PS 与新诱导的 PS 碰撞；否则，它们不会与原始 PS 相互作用。当 S3 冲击应用于相对不应期时，SW 转移最有效，并且 PS 沿 WT 方向转移。总之，PS 的定量跟踪表明，在理想条件下刺激会在 WT 上诱导成对 PS，并且 PS 的碰撞会导致 SW 沿 WT 移动。这项研究的结果表明，冲击诱导的兴奋与 WT 的相互作用对有效刺激的重要性。 新的和值得注意的是，刺激期间螺旋波动力学的定量分析阐明了捕获可兴奋间隙的作用机制，即刺激诱导 WT 上的成对相位奇点，以及由于这些相互作用导致的螺旋波沿 WT 移动。揭示了波尾对有效刺激的重要性。
