Optimal Cardiac Rhythm during Substrate Mapping in Scar-Related Ventricular Tachycardia: Significance of Wavefront Direction on Identifying Critical Sites.

BACKGROUND

A rotational activation pattern (RAP) around the localized line of a conduction block often correlates with sites specific to the critical zones of ventricular tachycardia (VT). The wavefront direction during substrate mapping affects the manifestation of the RAP and line of block.

OBJECTIVE

This study aimed to investigate the most optimal cardiac rhythm for identifying RAP and line of block in substrate mapping.

METHODS

We retrospectively evaluated 71 maps (median 3205 points/map) in 46 patients (65±15 years, 33% with ischemic cardiomyopathy) who underwent high-density substrate mapping and ablation of scar-related VT. The appearance of a RAP during sinus, right ventricular (RV)-paced, left ventricular (LV)-paced, and biventricular-paced rhythms was investigated.

RESULTS

The RAP was identified in 24 of 71 (34%) maps in the region where wavefronts from a single direction reached but not in the region where wavefronts from multiple directions centripetally collided. The probability of identifying the RAP depended on the scar location; that is, anteroseptal and inferoseptal, inferior and apical, and basal lateral RAPs were likely to be identified during sinus/atrial, RV-paced, and LV-paced rhythms, respectively. In 13 patients, the RAP was not evident in the baseline map but became apparent during remapping in the other rhythm, in which the wavefront reached the site earlier within the entire activation time.

CONCLUSIONS

The optimal rhythm for substrate mapping depends on the spatial distribution of the area of interest. A paced rhythm with pacing sites near the scar may facilitate the identification of critical VT zones.

Informations de copyright

Copyright © 2024. Published by Elsevier Inc.