Zeldin Lawrence, Majumder Jonah A, Yang Haiqiu, Yarmohammadi Hirad, Biviano Angelo, Hennessey Jessica, Wan Elaine Y, Ciaccio Edward J, Garan Hasan, Hendon Christine P, Saluja Deepak
Department of Medicine, Columbia University Irving Medical Center, New York, New York.
Department of Biomedical Engineering, Fu Foundation School of Engineering and Applied Science, Columbia University, New York, New York.
Heart Rhythm. 2025 May;22(5):1238-1248. doi: 10.1016/j.hrthm.2024.08.038. Epub 2024 Aug 22.
Catheter ablation of ventricular tachycardia (VT) during sinus rhythm often relies on isochronal late activation mapping (ILAM), a validated means of isthmus identification, whereby points are binned by local activation time (LAT) into 8 isochrones, and isthmus regions are identified as regions with isochronal crowding. The resulting output, however, is inherently discretized, and loss of LAT data occurs. To improve the precision of isthmus identification, we quantify isochronal density and assess the effect of increasing the number of isochrones used and the effectiveness of continuous metrics analogous to ILAM.
The objective of this study was to determine whether current practices in ILAM calculation are optimized for isthmus detection.
Patients undergoing VT ablation were included if high-density maps in both VT and sinus or paced rhythms were available. Isochronal density was assessed at differing numbers of isochrones, and isthmus discrimination was assessed. Continuous metrics that mimicked ILAM by assessing the local distribution of LAT values-using interquartile range or the median absolute deviation-were also defined and assessed.
Eight electroanatomic maps (EAMs) were included. Isthmus discrimination improved progressively from a minimum area under the curve (AUC) of 0.600 when assessing the isochronal density of 8-isochrone EAMs to a maximum of 0.776 when assessing the density of 1000-isochrone EAMs (DeLong test, P < .0001). On logistic regression, the continuous metrics using interquartile range (AUC = 0.714) and median absolute deviation (AUC = 0.721) better discriminated isthmus identity than ILAM.
Using more isochrones or using continuous ILAM analogues improves isthmus identification. By retaining more data, these metrics could increase the precision of VT ablation.
窦性心律时室性心动过速（VT）的导管消融通常依赖等时性晚期激动标测（ILAM），这是一种经过验证的峡部识别方法，即根据局部激动时间（LAT）将各点划分为8个等时线，峡部区域被识别为等时线密集的区域。然而，最终输出本质上是离散的，并且会出现LAT数据丢失的情况。为提高峡部识别的精度，我们对等时线密度进行量化，并评估增加所用等时线数量的效果以及类似于ILAM的连续指标的有效性。
本研究的目的是确定ILAM计算的当前做法是否针对峡部检测进行了优化。
纳入接受VT消融且同时有VT以及窦性或起搏心律的高密度图的患者。评估不同等时线数量下的等时线密度，并评估峡部辨别情况。还定义并评估了通过使用四分位间距或中位数绝对偏差来评估LAT值局部分布从而模拟ILAM的连续指标。
纳入8份电解剖图（EAM）。峡部辨别能力从评估8等时线EAM等时线密度时的曲线下面积（AUC）最小值0.600逐渐提高到评估1000等时线EAM密度时的最大值0.776（德龙检验，P <.0001）。在逻辑回归分析中，使用四分位间距（AUC = 0.714）和中位数绝对偏差（AUC = 0.721）这两个连续指标比ILAM能更好地辨别峡部特征。
使用更多等时线或使用连续的ILAM类似指标可改善峡部识别。通过保留更多数据，这些指标可提高VT消融的精度。
