Electrode-specific bipolar voltage cut-offs for substrate mapping in ischemic cardiomyopathy

Background

In patients with ischemic cardiomyopathy and ventricular tachycardia (VT), functional substrate mapping and ablation of evoked delayed potential (EDPs) have proven effective. Previous research suggests that multi-electrode catheters, with smaller and more closely spaced electrodes, may be superior to large single-tip electrodes.

Purpose

This two-center prospective study directly compares substrate mapping using conventional, micro-, and mini-electrodes.

Methods

Between June 2021 and March 2024, 21 post-myocardial infarction patients (median age 66 years old [61-76], 100% male, LVEF 39% [33-45]) undergoing VT ablation were systematically mapped with a single-tip (QDOT) and multi-electrode (Pentaray) catheter during sinus rhythm (SR) and right ventricular extrastimulation (RVE). Baseline patient characteristics, mapping data and outcomes were collected. Bipolar voltage (BV) maps (4830 and 9159 SR and 1166 and 3498 RVE points respectively) were analyzed offline and electrogram (EGM) characteristics were compared.

Results

Mapping times were significantly shorter with the multi-electrode catheter (24 [20-32] versus 57 minutes [49-73], P<0.0001) and produced significantly denser maps (392 [326-440] versus 222 [184-37281] SR and 158 [120-181] versus 52 [45-72] RVE mapping points, both P<0.0001). BV amplitudes were highest and EGM durations shortest when using micro-electrodes as compared with other electrodes. BV amplitudes recorded across electrode types were positively correlated, enabling the definition of electrode-specific BV cut-offs. Using these cut-offs, complex EGMs and EDPs consistently localized to low voltage areas.

Conclusions

Multi-electrode mapping is faster and yields denser maps, while micro-electrode mapping with a single-tip catheter provides the most accurate approximation of local activation. Applying electrode-specific BV cut-offs may improve EGM interpretation.

Figure legend:

Representative bipolar voltage maps of remodeled and non-remodeled left ventricle as recorded with conventional, micro- and mini-electrodes using different cut-off values. Orange tags indicate evoked delayed potentials.