Improved local activation time annotation of fractionated atrial electrograms for atrial mapping
Improved local activation time annotation of fractionated atrial electrograms for atrial mapping
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DOI：
10.1016/j.compbiomed.2019.103590
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发表时间：
2020-02-01
影响因子：
7.7
通讯作者：
de Groot, Natasja M. s
中科院分区：
文献类型：
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作者：
Abdi, Bahareh;Hendriks, Richard C.;de Groot, Natasja M. s
背景：单极电描记图中的局部激活时间（LAT）注释由于邻近组织的非局部心房活动的干扰而变得复杂。发生这种情况是由于电描记图记录固有的空间模糊所致。在本研究中，我们的目标是利用多电极电描记图记录来放大每个电描记图中的局部活动，并随后改进 LAT 的注释。方法：电描记图阵列可以建模为每个细胞跨膜电流与适当距离内核的空间卷积，该距离内核取决于细胞到电极的距离。通过对电描记图阵列的距离核的影响进行去卷积，我们消除了模糊并估计了潜在的跨膜电流作为我们期望的局部活动。然而，反卷积问题通常是高度不适定的并导致不稳定的解决方案。为了克服这个问题，我们建议使用正则化项，该项利用跨膜电流的一阶时间导数的稀疏性。结果：我们在模拟二维组织以及阵发性心房颤动期间临床记录的电图上进行了实验。结果表明，所提出的反卷积方法可以改进电描记图中真实 LAT 的注释。总之，我们还讨论了适当记录和随后的反卷积所需的电极阵列规格。结论：通过忽略小但局部的偏转，基于最速下降的算法易于生成更平滑的激活图。然而，通过利用多电极记录，我们可以有效地放大微小但局部的偏转，并揭示激活图中以前遗漏的新细节。
Background: Local activation time (LAT) annotation in unipolar electrograms is complicated by interference from nonlocal atrial activities of neighboring tissue. This happens due to the spatial blurring that is inherent to electrogram recordings. In this study, we aim to exploit multi-electrode electrogram recordings to amplify the local activity in each electrogram and subsequently improve the annotation of LATs.Methods: An electrogram array can be modeled as a spatial convolution of per cell transmembrane currents with an appropriate distance kernel, which depends on the cells' distances to the electrodes. By deconvolving the effect of the distance kernel from the electrogram array, we undo the blurring and estimate the underlying transmembrane currents as our desired local activities. However, deconvolution problems are typically highly ill-posed and result in unstable solutions. To overcome this issue, we propose to use a regularization term that exploits the sparsity of the first-order time derivative of the transmembrane currents.Results: We perform experiments on simulated two-dimensional tissues, as well as clinically recorded electrograms during paroxysmal atrial fibrillation. The results show that the proposed approach for deconvolution can improve the annotation of the true LAT in the electrograms. We also discuss, in summary, the required electrode array specifications for an appropriate recording and subsequent deconvolution.Conclusion: By ignoring small but local deflections, algorithms based on steepest descent are prone to generate smoother activation maps. However, by exploiting multi-electrode recordings, we can efficiently amplify small but local deflections and reveal new details in the activation maps that were previously missed.