Assessing the ability of substrate mapping techniques to guide ventricular tachycardia ablation using computational...

Area of Science:

• Computational modeling in cardiac electrophysiology.
• Cardiovascular research and medical device development.

Background:

• Identifying ablation targets for post-infarction ventricular tachycardias (VTs) is challenging, often requiring risky arrhythmia induction.
• Substrate mapping offers a safer alternative but frequently results in VT recurrence.

Purpose of the Study:

• To evaluate the efficacy of various substrate mapping techniques in pinpointing VT exit sites using computer simulations.
• To assess the impact of pacing location on mapping accuracy.

Main Methods:

• A 3D computational model of a porcine post-infarction heart was created to simulate VT and paced rhythms.
• Electrophysiological maps were generated using endocardial electrogram features and the reentry vulnerability index (RVI).
• Analysis incorporated parameters from all signals, including dense scar regions, to compare potential ablation targets with VT exit sites.

Main Results:

• Voltage cut-offs delineated scar but not VT circuits; electrogram fractionation correlated best with scar transmurality.
• The RVI showed proximity to VT exit sites, but activation-repolarization (AR) gradients with voltage cut-offs performed better.
• Pacing location significantly influenced the performance of all mapping metrics.

Conclusions:

• Substrate mapping provides infarct information, but directional activation dependency must be considered.
• Activation-repolarization metrics are valuable for safely identifying VT targets, particularly in cases with non-transmural scars.