Heart Rhythm O2 (Nov 2024)

Local atrial bipolar electrogram voltage drops during cardiac magnetic resonance guided catheter ablation of typical atrial flutter: Associations with delivered radiofrequency energy and peri-procedural imaging

  • Hedwig M.J.M. Nies, MD,
  • Dominik Linz, MD, PhD,
  • Geertruida P. Bijvoet, MD, PhD,
  • Robert J. Holtackers, PhD,
  • Justin G.L.M. Luermans, MD, PhD,
  • Kim E.H.M. van der Velden, MD,
  • Joachim E. Wildberger, MD, PhD,
  • Kevin Vernooy, MD, PhD,
  • Sander M.J. van Kuijk, PhD,
  • Casper Mihl, MD, PhD,
  • Sevasti-Maria Chaldoupi, MD, PhD

Journal volume & issue
Vol. 5, no. 11
pp. 778 – 787

Abstract

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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 T2-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.

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