Electrical and Anatomical Imaging of Arrhythmogenic Substrates for Scar-related Ventricular Tachycardia

Abstract

Sustained ventricular tachycardia (VT) often involves a reentry circuit formed by narrow channels of surviving tissue within the scar. Catheter ablation is an effective technique to intercept the circuit by targeting these critical channels. The success of VT ablation relies on our ability to assess the mechanism of the VT circuit and identify the location of the ablation targets. This study aims to analyze the VT substrate using high-resolution anatomical and electrical imaging techniques including contact EGM mapping, contrast-enhanced cardiac magnetic resonance (CMR) imaging, and noninvasive electrocardiographic (ECG) imaging. The results indicate that joint electro-anatomical analysis could reveal critical isthmus of the VT circuit. In addition, ECG-imaging was able to identify sites of a scar and signal fractionation visually consistent with the other two modalities, and the reconstructed VT circuit revealed an exit around the critical site identified by combined CMR-EGM data.

Noninvasive Electrocardiographic Imaging of Scar-Related Ventricular Tachycardia: Association With Magnetic Resonance Scar Imaging

“…Stacks of 2D MRI images were performed to identify the ECG electrodes. Imaging parameters for a T1-weighted gradient echo sequence with fat suppression were: reconstructed pixel size 1.1x1.1x1.1 mm, FOV = 400x400mm, matrix 384x307, bandwidth = 620 Hz/Pixel, breath hold for 20 seconds [8].…”

“…This is largely due to the lack of gold standard data regarding the VT circuit and the culprit conducting channels. Limited quantitative validation studies include two animal case studies that involves a torso-tank set up [1], and a recent human case study where ECGi solutions were compared to both late Gadolinium enhanced cardiac magnetic resonance (LGE-CMR) data and cathether mapping data [8].…”