Optimal Annotation of Local Activation Time in Ventricular Tachycardia Substrate Mapping.

Background: Accurate annotation of electrogram local activation time (LAT) is critical to the functional assessment of ventricular tachycardia (VT) substrate. Contemporary methods of annotation include: 1) earliest bipolar electrogram (LAT _earliest ); 2) peak bipolar electrogram (LAT _peak ); 3) latest bipolar electrogram (LAT _latest ); and 4) steepest unipolar -dV/dt (LAT _-dV/dt ). However, no direct comparison of these methods has been performed in a large dataset, and it is unclear which provides the optimal functional analysis of the VT substrate.
Objectives: This study sought to investigate the optimal method of LAT annotation during VT substrate mapping.
Methods: Patients with high-density VT substrate maps and a defined critical site for VT re-entry were included. All electrograms were annotated using 5 different methods: LAT _earliest , LAT _peak , LAT _latest , LAT-dV _/dt , and the novel steepest unipolar -dV/dt using a dynamic window of interest (LAT _DWOI ). Electrograms were also tagged as either late potentials and/or fractionated signals. Maps, utilizing each annotation method, were then compared in their ability to identify critical sites using deceleration zones.
Results: Fifty cases were identified with 1,.813 ± 811 points per map. Using LAT _latest , a deceleration zone was present at the critical site in 100% of cases. There was no significant difference with LAT _earliest (100%) or LAT _peak (100%). However, this number decreased to 54% using LAT _-dV/dt and 76% for LAT _DWOI . Using LAT-dV/dt, only 33% of late potentials were correctly annotated, with the larger far field signals often annotated preferentially.
Conclusions: Annotation with LAT _-dV/dt and LAT _DWOI are suboptimal in VT substrate mapping. We propose that LAT _latest should be the gold standard annotation method, as this allows identification of critical sites and is most suited to automation.
Competing Interests: Funding Support and Author Disclosures Dr Hsia has received honoraria from Biosense Webster, FaraPulse, and Medtronic. Dr Kistler has received an investigator grant from the National Health and Medical Research Council of Australia; and speaker honoraria and fellowship support from Biosense Webster. Dr Kumar has received honoraria from Biosense Webster, Abbott Medical, Biotronik, and Sanofi. Dr Kalman has received a National Health and Medical Research Council of Australia practitioner fellowship; and research and fellowship support from Biosense Webster, Abbott, and Medtronic. Dr Lee has received consulting fees and speaker honoraria from Biosense Webster. Dr Gerstenfeld has received honoraria from Biosense Webster, Boston Scientific, Medtronic, and Abbott Medical; received research support from Abbott Medical; and served on the scientific advisory board for Biosense Webster, Farapulse/Boston Scientific, and Adagio medical. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
(Copyright © 2024 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)