Virtual electrode polarization in the far field: implications for external defibrillation
Virtual electrode polarization in the far field: implications for external defibrillation
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DOI：
10.1152/ajpheart.2000.279.3.h1055
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发表时间：
2000-09-01
影响因子：
4.8
通讯作者：
Trayanova, N
中科院分区：
文献类型：
--
作者：
Efimov, IR;Aguel, F;Trayanova, N
我们最近提出植入式除颤治疗的失败可以用虚拟电极诱导的相位奇异机制来解释。本研究的目的是确定体外体外施加的易损性和除颤的可能机制。我们使用真实的兔心脏纤维几何形状的双域模拟来预测外部冲击引起的整个心脏的被动极化。我们还使用光学作图来评估langendorff灌注兔心脏在电击期间的前心外膜电活动（n = 7）。在一对网状电极的T波期间施加任一极性的单相冲击（10-260 V, 8 ms, 150 mu F）。在所有162次冲击后观察到心外膜虚电极的冲击后极化，正如双畴模拟预测的那样，正极化面向阴极，负极化面向阳极。在心律失常发生过程中，新的波阵面在靠近心尖的两个区域的边界处产生，而在基底处没有。它穿过负极化区向心脏底部扩散，并在另一侧重新进入，同时向心壁深处扩散。因此，在外部电击诱发的心律失常过程中，会形成带带状细丝的涡旋波。荧光成像和被动双畴模拟表明，虚拟电极极化诱导的涡旋波是冲击诱导的易损和体外除颤失败机制的基础。
We recently suggested that failure of implantable defibrillation therapy may be explained by the virtual electrode-induced phase singularity mechanism. The goal of this study was to identify possible mechanisms of vulnerability and defibrillation by externally applied shocks in vitro. We used bidomain simulations of realistic rabbit heart fibrous geometry to predict the passive polarization throughout the heart induced by external shocks. We also used optical mapping to assess anterior epicardium electrical activity during shocks in Langendorff-perfused rabbit hearts (n = 7). Monophasic shocks of either polarity (10-260 V, 8 ms, 150 mu F) were applied during the T wave from a pair of mesh electrodes. Postshock epicardial virtual electrode polarization was observed after all 162 applied shocks, with positive polarization facing the cathode and negative polarization facing the anode, as predicted by the bidomain simulations. During arrhythmogenesis, a new wave front was induced at the boundary between the two regions near the apex but not at the base. It spread across the negatively polarized area toward the base of the heart and reentered on the other side while simultaneously spreading into the depth of the wall. Thus a scroll wave with a ribbon-shaped filament was formed during external shock-induced arrhythmia. Fluorescent imaging and passive bidomain simulations demonstrated that virtual electrode polarization-induced scroll waves underlie mechanisms of shock-induced vulnerability and failure of external defibrillation.