Sahakian A V, Peterson M S, Shkurovich S, Hamer M, Votapka T, Ji T, Swiryn S
Department of Electrical and Computer Engineering, Northwestern University, Evanston, IL 60208, USA.
IEEE Trans Biomed Eng. 2001 Mar;48(3):345-53. doi: 10.1109/10.914798.
While the recording of extracellular monophasic action potentials (MAPs) from single epicardial or endocardial sites has been performed for over a century, we are unaware of any previous successful attempt to record MAPs simultaneously from a large number of sites in vivo. We report here the design and validation of an array of MAP electrodes which records both depolarization and repolarization simultaneously at up to 16 epicardial sites in a square array on the heart in vivo. The array consists of 16 sintered Ag-AgCl electrodes mounted in a common housing with individual suspensions allowing each electrode to exert a controlled pressure on the epicardial surface. The electrodes are arranged in a square array, with each quadrant of four having an additional recessed sintered Ag-AgCl reference electrode at its center. A saline-soaked sponge establishes ionic contact between the reference electrodes and the tissue. The array was tested on six anesthetized open-chested pigs. Simultaneous diagnostic-quality MAP recordings were obtained from up to 13 out of 16 ventricular sites. Ventricular MAPs had amplitudes of 10-40 mV with uniform morphologies and stable baselines for up to 30 min. MAP duration at 90% repolarization was measured and shown to vary as expected with cycle length during sustained pacing. The relationship between MAP duration and effective refractory period was also confirmed. The ability of the array to detect local differences in repolarization was tested in two ways. Placement of the array straddling the atrioventricular (AV) junction yielded simultaneous atrial or ventricular recordings at corresponding sites during 1:1 and 2:1 AV conduction. Localized ischemia via constriction of a coronary artery branch resulted in shortening of the repolarization phase at the ischemic, but not the nonischemic, sites. In conclusion, these results indicate that the simultaneous multichannel MAP electrode array is a viable method for in vivo epicardial repolarization mapping. The array has the potential to be expanded to increase the number of sites and spatial resolution.
虽然从单个心外膜或心内膜位点记录细胞外单相动作电位（MAPs）已有一个多世纪的历史，但我们不知道此前有任何在体内从大量位点同时记录MAPs的成功尝试。我们在此报告一种MAP电极阵列的设计与验证，该阵列可在体内心脏的方形阵列中同时记录多达16个心外膜位点的去极化和复极化过程。该阵列由16个烧结银 - 氯化银电极组成，安装在一个共同的外壳中，每个电极都有单独的悬架，使每个电极能够对心外膜表面施加可控压力。电极排列成方形阵列，每四个电极组成的象限在其中心还有一个额外的凹陷烧结银 - 氯化银参考电极。一块浸有盐水的海绵在参考电极与组织之间建立离子接触。该阵列在六只麻醉开胸猪身上进行了测试。从16个心室位点中的多达13个位点获得了同步的诊断质量的MAP记录。心室MAPs的幅度为10 - 40 mV，形态均匀，基线稳定长达30分钟。测量了90%复极化时的MAP持续时间，并显示在持续起搏期间随周期长度按预期变化。MAP持续时间与有效不应期之间的关系也得到了证实。该阵列检测复极化局部差异的能力通过两种方式进行了测试。将阵列放置在跨越房室（AV）交界处，在1:1和2:1房室传导期间，在相应位点可同时记录心房或心室信号。通过冠状动脉分支的收缩造成局部缺血，导致缺血位点而非非缺血位点的复极化阶段缩短。总之，这些结果表明，同步多通道MAP电极阵列是一种可行的体内心外膜复极化标测方法。该阵列有潜力进行扩展以增加位点数量和空间分辨率。
