Cardiac response to low-energy field pacing challenges the standard theory of defibrillation.
Cardiac response to low-energy field pacing challenges the standard theory of defibrillation.
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DOI：
10.1161/circep.114.002661
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发表时间：
2015-06
期刊：
影响因子：
--
通讯作者：
Pertsov AM
中科院分区：
文献类型：
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作者：
Caldwell BJ;Trew ML;Pertsov AM
心肌组织对周期性场刺激的电反应作为低能量抗颤起搏（LEAP）的基础引起了人们的广泛关注，它可能比传统的单一高能量电击更有效。在传统模型中，电场会产生心肌壁高度不均匀的响应，在阴极组织表面或大冠状血管处出现离散激励或“热点”(HS)。我们使用新颖的 3D 断层光学成像来测试这一预测。实验在用近红外电压敏感荧光染料 DI-4-ANBDQBS 染色的离体冠状动脉灌注猪心室壁制剂中进行。使用交替透照法确定 HS 的 3D 坐标。为了将 HS 形成与心肌结构联系起来，我们使用了超深共焦成像（询问深度 >4 毫米）。峰值 HS 分布位于心壁深处，并且该深度不受场极性的显着影响。我们没有观察到 HS 与理论上预期的主要冠状血管的强烈共定位。然而，我们观察到随着场极性反转，HS 发生相当大的横向位移。不强调横向细胞内耦合并考虑细胞外空间电阻异质性的模型显示出与实验观察结果相似的 HS 分布。心肌壁内的 HS 分布以及场极性反转时的显着横向位移与除颤的标准理论不一致。基于细胞尺度电机制的增强描述的扩展理论可能是必要的。场极性反转时 HS 的相当大的横向位移支持了 LEAP 中双相刺激有利的假设。
The electrical response of myocardial tissue to periodic field stimuli has attracted significant attention as the basis for low-energy anti-fibrillation pacing (LEAP), potentially more effective than traditional single high-energy shocks. In conventional models, an electric field produces a highly non-uniform response of the myocardial wall, with discrete excitations, or “hot spots” (HS), occurring at cathodal tissue surfaces or large coronary vessels. We test this prediction using novel 3D tomographic optical imaging. Experiments were performed in isolated coronary perfused pig ventricular wall preparations stained with near-infrared voltage-sensitive fluorescent dye DI-4-ANBDQBS. The 3D coordinates of HS were determined using alternating transillumination. To relate HS formation with myocardial structures we used ultra-deep confocal imaging (interrogation depths >4 mm). The peak HS distribution is located deep inside the heart wall and the depth is not significantly affected by field polarity. We did not observe the strong co-localization of HS with major coronary vessels anticipated from theory. Yet, we observed considerable lateral displacement of HS with field polarity reversal. Models that deemphasized lateral intracellular coupling and accounted for resistive heterogeneity in the extracellular space showed similar HS distributions to the experimental observations. The HS distributions within the myocardial wall and the significant lateral displacements with field polarity reversal are inconsistent with standard theories of defibrillation. Extended theories based around enhanced descriptions of cellular scale electrical mechanisms may be necessary. The considerable lateral displacement of HS with field polarity reversal supports the hypothesis of biphasic stimuli in LEAP being advantageous.