Horáček B Milan, Wang Linwei, Dawoud Fady, Xu Jingjia, Sapp John L
Dalhousie University, Halifax, NS, Canada.
Rochester Institute of Technology, Rochester, NY, USA.
J Electrocardiol. 2015 Nov-Dec;48(6):952-8. doi: 10.1016/j.jelectrocard.2015.08.035. Epub 2015 Aug 28.
Myocardial infarction (MI) scar constitutes a substrate for ventricular tachycardia (VT), and an accurate delineation of infarct scar may help to identify reentrant circuits and thus facilitate catheter ablation. One of the recent advancements in characterization of a VT substrate is its volumetric delineation within the ventricular wall by noninvasive electrocardiographic imaging. This paper compares, in four specific cases, epicardial and volumetric inverse solutions, using magnetic resonance imaging (MRI) with late gadolinium enhancement as a gold standard.
For patients with chronic MI, who presented at Glasgow Western Infirmary, delayed-enhancement MRI and 120-lead body surface potential mapping (BSPM) data were acquired and 4 selected cases were later made available to a wider community as part of the 2007 PhysioNet/Computers in Cardiology Challenge. These data were used to perform patient-specific inverse solutions for epicardial electrograms and morphology-based criteria were applied to delineate infarct scar on the epicardial surface. Later, the Rochester group analyzed the same data by means of a novel inverse solution for reconstructing intramural transmembrane potentials, to delineate infarct scar in three dimensions. Comparison of the performance of three specific inverse-solution algorithms is presented here, using scores based on the 17-segment ventricular division scheme recommended by the American Heart Association.
The noninvasive methods delineating infarct scar as three-dimensional (3D) intramural distribution of transmembrane action potentials outperform estimates providing scar delineation on the epicardial surface in all scores used for comparison. In particular, the extent of infarct scar (its percentage mass relative to the total ventricular mass) is rendered more accurately by the 3D estimate. Moreover, the volumetric rendition of scar border provides better clues to potential targets for catheter ablation.
Electrocardiographic inverse solution providing transmural distribution of ventricular action potentials is a promising tool for noninvasively delineating the extent and location of chronic MI scar. Further validation on a larger data set with detailed gold-standard data is needed to confirm observations reported in this study.
心肌梗死（MI）瘢痕是室性心动过速（VT）的一个基质，准确描绘梗死瘢痕可能有助于识别折返环路，从而便于导管消融。VT基质特征描述的最新进展之一是通过无创心电图成像在心室壁内进行容积描绘。本文在四个特定病例中，以磁共振成像（MRI）延迟钆增强作为金标准，比较心外膜和容积逆解。
对于在格拉斯哥西部医院就诊的慢性MI患者，获取延迟增强MRI和120导联体表电位标测（BSPM）数据，4例选定病例随后作为2007年生理网/心脏病学计算机挑战赛的一部分提供给更广泛的群体。这些数据用于进行心外膜电图的患者特异性逆解，并应用基于形态学的标准描绘心外膜表面的梗死瘢痕。后来，罗切斯特小组通过一种用于重建壁内跨膜电位的新型逆解分析相同数据，以三维方式描绘梗死瘢痕。本文使用基于美国心脏协会推荐的17节段心室划分方案的评分，比较三种特定逆解算法的性能。
在所有用于比较的评分中，将梗死瘢痕描绘为跨膜动作电位的三维（3D）壁内分布的无创方法优于在心外膜表面进行瘢痕描绘的估计方法。特别是，3D估计能更准确地呈现梗死瘢痕的范围（其相对于全心室质量的质量百分比）。此外，瘢痕边界的容积呈现为导管消融的潜在靶点提供了更好的线索。
提供心室动作电位跨壁分布的心电图逆解是一种有前景的工具，可用于无创描绘慢性MI瘢痕的范围和位置。需要在更大的数据集上进行进一步验证，并结合详细的金标准数据，以证实本研究报告的观察结果。
