Non-invasive epicardial and endocardial electrocardiographic imaging for scar-related ventricular tachycardia

Abstract

Background-The majority of life-threatening ventricular tachycardias (VTs) are sustained by heterogeneous scar substrates with narrow strands of surviving tissue. An effective treatment for scar-related VT is to modify the underlying scar substrate by catheter ablation. If activation sequence and entrainment mapping can be performed during sustained VT, the exit and isthmus of the circuit can often be identified. However, with invasive catheter mapping, only monomorphic VT that is hemodynamically stable can be mapped in this manner. For the majority of patients with poorly tolerated VTs or multiple VTs, a close inspection of the reentry circuit is not possible. A noninvasive approach to fast mapping of unstable VTs can potentially allow an improved identification of critical ablation sites.

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

“…From electrograms reconstructed during sinus rhythm, two features were extracted: the voltage was calculated as the difference between the highest and lowest deflections of each signal (QRS component), and the duration of QRS complex was manually measured. On electrograms reconstructed during induced VT, phase mapping was performed to visually track the spatiotemporal pattern of VT [6].…”

“…Bad leads were manually discarded. Noises were removed by wavelet filtering, and baseline correction was performed by fitting and subtracting from the signal a polynomial approximation of the waveform [6].…”

“…Electricardiographic imaging (ECGi) is a non-invasive approach to reconstructing electrical signals on the heart by combining high-density surface ECGs and geometries of the heart and torso [5]. It has the potential to provide a noninvasive adjunct to catheter mapping by allowing rapid mapping of all inducible stable or unstable VTs, and by allowing electrical mapping of scar substrates in a completely noninvasive manner before the procedure [6].…”

Mechanisms of Arrhythmogenicity in Hypertrophic Cardiomyopathy: Insight From Non-invasive Electrocardiographic Imaging

“…In this study, we used the Forward/Inverse problem toolkit from the SCIRun problem-solving environment, which is used by many investigators in the field (Burton et al, 2011;Coll-Font et al, 2014;Cluitmans et al, 2018;Wang et al, 2018). However, knowing the limitations of the ECGi method (Duchateau et al, 2019), we intentionally limited our analysis by averaged "per segment" data.…”

Validation and Opportunities of Electrocardiographic Imaging: From Technical Achievements to Clinical Applications

“…For VT mapping, a small number of human studies have investigated the use of ECGI to map the exit sites and activation pattern of reentry circuits, using both epicardial ECGI ( Wang et al, 2011 ; Sapp et al, 2012 ; Zhang et al, 2012 ) and more recently using epicardial-endocardial and 3D ECGI ( Tsyganov et al, 2017 ; Wang et al, 2018 ). For substrate mapping, while the use of ECGI to delineate myocardial scar has been validated using MRI or voltage mapping ( Cuculich et al, 2011 ; Wang et al, 2013 ; Horáček et al, 2015 ), studies are just emerging to examine its ability to reveal local abnormal electrograms, such as fractionated electrograms, that are suggestive of potential central pathways forming the VT circuit ( Wang et al, 2018 ). In all of these studies, a significant challenge arises from the difficulty to establish the clinical ground truth for the exit sites and central pathway for VT; as a result, most existing validation studies are limited to qualitative or semi-quantitative evaluations.…”