SPIRAL WAVES IN ISOLATED VENTRICULAR MYOCARDIUM

再入已被认为是导致 室性心律失常。因为折返性心动过速会导致 室颤和猝死，重要的是要了解 他们的病理生理学。在无心律失常的情况下可能会发生折返性心律失常。 一个解剖学上预先设定的回路。建议的机制 实验电生理学家解释功能确定 再入大气层的概念是基于围绕 功能上的“洞”。另一方面，理论和实验相结合 基于波在其他类型的可激发介质中的传播的研究，例如 正如别洛索夫-扎博廷斯基反应所显示的那样，自持旋转 螺旋波形式的活动在均匀状态下是明显的。 系统。这项研究的总体目标是使用新开发的 螺旋波动力学理论研究中的概念 在可兴奋介质中提供对电生理基础的洞察 室性折返性心律失常。这些概念的适用性 对心律失常机制的认识是最近才开始的。 由本实验室报告的实验研究支持(1-3)。 具体目标是：1)开发具有以下功能的光学测绘系统 直接观测螺旋线的最佳时空分辨率 在分离的心室肌中的波。2)确定 稳态和非稳态螺旋波；以及3)确定 螺旋波在传播形式摄动过程中的动力学 由电刺激引起的波。以下假设将 被测试：1)螺旋波可以表现为静止或非静止 静止状态取决于：a)电生理参数： 0相特征和动作电位时程；b)相互作用 具有可激发介质边界的旋转波；2)A 非平稳螺旋波漂移(它可能改变位置)。然而， 细小的非均质性的存在可能有助于锚定旋转 活动，并将非稳定的螺旋波转换为稳定的螺旋波； 3)螺旋波的核心可能由于以下原因而移动到适当的位置- 阈值刺激。漂移的方向和速度将 取决于螺旋波的相位和刺激率。 然而，直接在核心施加刺激可能会产生漂移或 以独立于阶段的方式终止。我们的初步结果 强烈建议高分辨率光学测绘应该允许 离体心包内螺旋波的详细定量研究 心肌。建议的实验将直接和准确地给出 关于孤立的两颗行星持续重返大气层的细胞基础的解答- 空间心肌和NAT可以提供对 室性心动过速的病理生理。

Reentry has been recognized as the major mechanism responsible for ventricular arrhythmias. Because reentrant tachycardias can lead to ventricular fibrillation and sudden death, it is important to understand their pathophysiology. Reentrant arrhythmias may occur in the absence of an anatomically predetermined circuit. Mechanisms proposed by experimental electrophysiologists to explain functionally determined reentry are based on the concept of circulation of propagation around a functional "hole". On the other hand, theoretical and experimental studies based on wave propagation in other types of excitable media, such as the Belousov-Zhabotinsky reaction, show that self-sustained rotating activity, in the form of spiral waves, is demonstrable in homogeneous systems. The overall objective of this study is to use newly developed concepts derived from theoretical studies on the dynamics of spiral waves in excitable media to provide insight into the electrophysiological bases of ventricular reentrant arrhythmias. The applicability of such concepts to the understanding of mechanisms of arrhythmias has been recently supported by experimental studies reported from our laboratory (1-3). The specific aims are: 1) To develop an optical mapping system with optimal spatio-temporal resolution for the direct observation of spiral waves in isolated ventricular muscle. 2) To determine the mechanisms of stationary and non-stationary spiral waves; and 3) To determine the dynamics of spiral waves during perturbations in the form of propagating waves initiated by electrical stimulation. The following hypotheses will be tested: 1) Spiral waves may exhibit either stationary or non- stationary states depending on: a) electrophysiological parameters: characteristics of phase 0 and action potential duration; b) interaction of the rotating waves with the boundaries of the excitable medium; 2) A non-stationary spiral wave drift (it may change in position). However, the presence of small heterogeneities may serve to anchor the rotating activity and convert a non-stationary spiral wave into a stationary one; 3) The core of a spiral wave may be shifted in place as a result of just- threshold stimulation. The direction and velocity of the drift will depend on the phase of the spiral wave and the rate of stimulation. However, stimulation applied directly at the core may produce drift or termination in a phase-independent manner. Our preliminary results strongly suggest that high resolution optical mapping should allow a detailed quantitative study of spiral waves in isolated ventricular myocardium. The proposed experiments will give direct and accurate answers about the cellular basis of sustained reentry in isolated two- dimensional cardiac muscle and nay provide insight into the pathophysiology of ventricular tachycardia.