Schaufelberger Matthias, Schuler Steffen, Bear Laura, Cluitmans Matthijs, Coll-Font Jaume, Onak Önder Nazim, Dössel Olaf, Brooks Dana
Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany.
IHU-LIRYC Electrophysiology and Heart Modeling Institute, Pessac-Bordeaux, France.
Comput Cardiol (2010). 2019 Sep;46. doi: 10.22489/cinc.2019.379. Epub 2020 Feb 24.
Activation times (AT) describe the sequence of cardiac depolarization and represent one of the most important parameters for analysis of cardiac electrical activity. However, estimation of ATs can be challenging due to multiple sources of noise such as fractionation or baseline wander. If ATs are estimated from signals reconstructed using electrocardiographic imaging (ECGI), additional problems can arise from over-smoothing or due to ambiguities in the inverse problem. Often, resulting AT maps show falsely homogeneous regions or artificial lines of block. As ATs are not only important clinically, but are also commonly used for evaluation of ECGI methods, it is important to understand where these errors come from. We present results from a community effort to compare methods for AT estimation on a common dataset of simulated ventricular pacings. ECGI reconstructions were performed using three different surface source models: transmembrane voltages, epi-endo potentials and pericardial potentials, all using 2nd-order Tikhonov and 6 different regularization parameters. ATs were then estimated by the community participants and compared to the ground truth. While the pacing site had the largest effect on AT correlation coefficients (CC larger for lateral than for septal pacings), there were also differences between methods and source models that were poorly reflected in CCs. Results indicate that artificial lines of block are most severe for purely temporal methods. Compared to the other source models, ATs estimated from transmembrane voltages are more precise and less prone to artifacts.
激活时间（AT）描述了心脏去极化的顺序，是分析心脏电活动的最重要参数之一。然而，由于存在诸如碎裂或基线漂移等多种噪声源，AT的估计可能具有挑战性。如果从使用心电图成像（ECGI）重建的信号中估计AT，则可能会因过度平滑或逆问题中的模糊性而出现其他问题。通常，由此产生的AT图会显示出虚假的均匀区域或人为的阻滞线。由于AT不仅在临床上很重要，而且还常用于评估ECGI方法，因此了解这些误差的来源很重要。我们展示了一项社区努力的结果，该努力旨在比较在模拟心室起搏的公共数据集上进行AT估计的方法。使用三种不同的表面源模型进行ECGI重建：跨膜电压、心外膜-心内膜电位和心包电位，均使用二阶蒂霍诺夫正则化和6个不同的正则化参数。然后由社区参与者估计AT，并与真实值进行比较。虽然起搏部位对AT相关系数的影响最大（外侧起搏的CC大于间隔起搏），但方法和源模型之间的差异在CC中反映不佳。结果表明，对于纯时间方法，人为的阻滞线最为严重。与其他源模型相比，从跨膜电压估计的AT更精确，且更不易出现伪影。
