Pace-mapping Methods for Scar-related Ventricular Tachycardia

Abstract

In the treating of scar-related ventricular tachycardia（VT）, the goal is to identify the VT circuit and ablate critical slow conduction areas when their hemodynamics are stable. However, if the VT is hemodynamically intolerated, the focus shifts to identifying and ablating the substrate. Among available techniques, pace-mapping is particularly useful, as it helps identify the origin of ventricular arrhythmias and pinpoint abnormal conduction pathways, thereby aiding in the identification of VT substrates. This technique has been widely employed since the early stages of catheter ablation. However, with technological advancements such as three-dimensional mapping systems, it has become evident that VT conduction circuits exhibit three-dimensional characteristics, and there is a relationship between these circuits and delayed conduction properties in substrate mapping. Therefore, it is crucial to utilize mapping systems to visualize and comprehend the VT circuit in three dimensions during catheter treatment. This review provides an overview of the basic knowledge and clinical applications of the pace-mapping method, its limitations, and our findings on estimating three-dimensional VT circuits based on abrupt changes in the pace-mapping waveform caused by conduction delays and barriers within the VT circuit. In addition, we discuss recent insights into the pace-mapping method based on the latest studies.