Probing field-induced tissue polarization using transillumination fluorescent imaging.
Probing field-induced tissue polarization using transillumination fluorescent imaging.
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DOI：
10.1016/j.bpj.2010.07.057
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发表时间：
2010-10
影响因子：
3.4
通讯作者：
B. Caldwell;M. Wellner;B. Mitrea;A. Pertsov;C. Zemlin
中科院分区：
文献类型：
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作者：
B. Caldwell;M. Wellner;B. Mitrea;A. Pertsov;C. Zemlin
尽管生物物理理论在预测心脏内电击的影响方面取得了巨大的成功，但最近的光学标测研究揭示了理论和实验之间的两个主要差异：1)在强烈电击时记录的负体极化的存在；2)电击电极下出人意料的小表面极化。对于这些差异是由于实验技术的缺陷、组织损伤的伪影还是现有理论的缺陷，几乎没有达成一致意见。在这里，我们利用最近开发的近红外电压敏感染料和透光光学成像技术，首次对完好的室壁深处的场效应进行了非侵入性探测。这项技术消除了以前实验研究中遇到的一些限制。我们明确地证明，在完整的心肌组织制备的深处，强烈的电击确实会产生相当大的负体极化，这一点以前从表面记录中推断出来。我们还证明，与理论相反，接近阈值的舒张场刺激可激活距离阴极面2-6 mm的深层心肌层。使用Bidomain模拟，我们探索了可能提高理论和实验之间的一致性的因素。结果表明，负不对称电流的引入可以定性地解释不连续的双域模型中的负体极化现象。
Despite major successes of biophysical theories in predicting the effects of electrical shocks within the heart, recent optical mapping studies have revealed two major discrepancies between theory and experiment: 1), the presence of negative bulk polarization recorded during strong shocks; and 2), the unexpectedly small surface polarization under shock electrodes. There is little consensus as to whether these differences result from deficiencies of experimental techniques, artifacts of tissue damage, or deficiencies of existing theories. Here, we take advantage of recently developed near-infrared voltage-sensitive dyes and transillumination optical imaging to perform, for the first time that we know of, noninvasive probing of field effects deep inside the intact ventricular wall. This technique removes some of the limitations encountered in previous experimental studies. We explicitly demonstrate that deep inside intact myocardial tissue preparations, strong electrical shocks do produce considerable negative bulk polarization previously inferred from surface recordings. We also demonstrate that near-threshold diastolic field stimulation produces activation of deep myocardial layers 2–6 mm away from the cathodal surface, contrary to theory. Using bidomain simulations we explore factors that may improve the agreement between theory and experiment. We show that the inclusion of negative asymmetric current can qualitatively explain negative bulk polarization in a discontinuous bidomain model.