Optimal Annotation of Local Activation Time in Ventricular Tachycardia Substrate Mapping

Joshua Hawson; Robert D Anderson; Souvik K Das; Ahmed Al-Kaisey; David Chieng; Louise Segan; Troy Watts; Timothy Campbell; Joseph Morton; Alexander McLellan; Paul Sparks; Adam Lee; Edward P Gerstenfeld; Henry H Hsia; Aleksandr Voskoboinik; Bhupesh Pathik; Saurabh Kumar; Peter M Kistler; Jonathan Kalman; Geoffrey Lee

doi:10.1016/j.jacep.2023.10.014

Optimal Annotation of Local Activation Time in Ventricular Tachycardia Substrate Mapping

JACC Clin Electrophysiol. 2024 Feb;10(2):206-218. doi: 10.1016/j.jacep.2023.10.014. Epub 2023 Dec 13.

Authors

Joshua Hawson¹, Robert D Anderson¹, Souvik K Das¹, Ahmed Al-Kaisey¹, David Chieng², Louise Segan², Troy Watts³, Timothy Campbell⁴, Joseph Morton³, Alexander McLellan³, Paul Sparks³, Adam Lee⁵, Edward P Gerstenfeld⁵, Henry H Hsia⁵, Aleksandr Voskoboinik², Bhupesh Pathik³, Saurabh Kumar⁶, Peter M Kistler², Jonathan Kalman¹, Geoffrey Lee⁷

Affiliations

¹ Department of Cardiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia; Faculty of Medicine, Dentistry and Health Science, University of Melbourne, Melbourne, Victoria, Australia.
² Faculty of Medicine, Dentistry and Health Science, University of Melbourne, Melbourne, Victoria, Australia; Department of Cardiology, The Alfred Hospital, Melbourne, Victoria, Australia.
³ Department of Cardiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia.
⁴ Department of Cardiology, Westmead Hospital and Westmead Applied Research Centre, Westmead, New South Wales, Australia.
⁵ Division of Cardiology, Department of Medicine, University of California-San Francisco, San Francisco, California, USA.
⁶ Department of Cardiology, Westmead Hospital and Westmead Applied Research Centre, Westmead, New South Wales, Australia; Western Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.
⁷ Department of Cardiology, Royal Melbourne Hospital, Melbourne, Victoria, Australia; Faculty of Medicine, Dentistry and Health Science, University of Melbourne, Melbourne, Victoria, Australia. Electronic address: geoff.lee@mh.org.au.

PMID: 38099880
DOI: 10.1016/j.jacep.2023.10.014

Abstract

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.

Keywords: ILAM; functional substrate mapping; ventricular arrhythmias; ventricular tachycardia.

MeSH terms

Arrhythmias, Cardiac
Catheter Ablation* / methods
Electrocardiography / methods
Humans
Tachycardia, Ventricular* / surgery