Abstract

Background: Cardiac magnetic resonance (CMR)-guided catheter ablation of the cavotricuspid isthmus (CTI) has been proven feasible, but determinants of local electrogram (EGM) voltage drops during radiofrequency (RF) applications are unknown. Objective: The purpose of this study was to investigate local atrial bipolar EGM voltage drops and the association with delivered RF energy and anatomical information derived from peri-procedural CMR imaging. Methods: In consecutive patients undergoing CMR-guided CTI ablation procedures, relative EGM voltage drops for RF applications ≥20 seconds were calculated. Pre- and post-ablation CMR imaging was performed. Associations of relative EGM voltage drops with patient characteristics, delivered RF energy, and CTI anatomy were analyzed. Results: In total, 216 RF applications were evaluated from 12 patients (18 ± 5 applications/patient). EGM voltage amplitude at baseline was significantly higher in the group with the strongest relative EGM voltage drop (P < .05), whereas RF ablation settings (duration, power, temperature) and lesion characteristics (impedance drop, slope of impedance drop) did not differ. The EGM voltage amplitude at baseline (P < .001), left ventricular ejection fraction (LVEF) (P = .020), right atrium volume index (RAVI) (P = .027), and CTI line length (P = .026) showed the strongest association with relative EGM voltage drop. Four of 12 patients (33%) underwent a re-do procedure, 2 patients showed a regional late reconnection, which could be visually identified in the T 2-weighted images (T2WI) of the index procedure. Conclusion: Local EGM voltage amplitude, LVEF, RAVI, and CTI length are associated with relative EGM voltage drop during CMR-guided CTI ablation. Post-ablation CMR imaging during the index procedure may help to identify areas of late reconnection.

Original languageEnglish
Pages (from-to)778-787
Number of pages10
JournalHeart Rhythm O2
Volume5
Issue number11
Early online date1 Jan 2024
DOIs
Publication statusPublished - Nov 2024

Keywords

  • Ablation lesion assessment
  • Atrial flutter
  • Durable ablation lesion formation
  • Interventional cardiac MRI (iCMR)
  • Late electrical reconnection
  • Local atrial bipolar electrogram
  • Radiofrequency catheter ablation

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