The Evolution of Ventricular Scar Substrate Assessment by Using High-Resolution Mapping Platforms: Ongoing Quest for “Ground Truth”*

摘要

Substrate identification facilitated by electroa-natomic mapping (EAM) technologies has emerged as the foundation of catheter ablation for ventricular tachycardia (VT) in structural heart disease (1). Because re-entry is typically the mechanism of scar-related VT, substrate mapping techniques focus on: 1) differentiating normal versus abnormal areas of myocardial tissue; and 2) identifying the underlying arrhythmogenic pathophysiological substrate, typically within areas of scar, that contribute to the formation of re-entrant VT circuits. Evaluation of intracardiac bipolar electrogram (EGM) recordings is the basis of substrate mapping and has been used for decades. The development of specific criteria to identify ventricular scar tissue and arrhythmogenic substrate has largely been based on bipolar voltage amplitude and duration cutoff values along with identification of specific morphological characteristics such as fractionated, split, and late potentials (2). The goal is to accurately identify signal characteristics indicative of abnormal myocardial tissue. In this context, histological data are representative of “ground truth,” with all other modalities from the 12-lead electrocardiogram to more complex techniques such as advanced cardiac imaging and high-resolution EAM providing reasonable inferences that can be used clinically to identify abnormal areas of interest.