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Mechanism and magnitude of bipolar electrogram directional sensitivity: Characterizing underlying determinants of bipolar amplitude.

Publication ,  Journal Article
Gaeta, S; Bahnson, TD; Henriquez, C
Published in: Heart Rhythm
May 2020

BACKGROUND: The amplitude of bipolar electrograms (EGMs) is directionally sensitive, decreasing when measured from electrode pairs oriented oblique to a propagating wavefront. OBJECTIVE: The purpose of this study was to use a computational model and clinical data to establish the mechanism and magnitude of directional sensitivity. METHODS: Simulated EGMs were created using a computational model with electrode pairs rotated relative to a passing wavefront. A clinical database of 18,740 EGMs with varying electrode separation and orientations was recorded from the left atrium of 10 patients with atrial fibrillation during pacing. For each EGM, the angle of incidence between the electrodes and the wavefront was measured using local conduction velocity (CV) mapping. RESULTS: A theoretical model was derived describing the effect of the changing angle of incidence, electrode spacing, and CV on the local activation time difference between a pair of electrodes. Model predictions were validated using simulated and clinical EGMs. Bipolar amplitude measured by an electrode pair is decreased (directionally sensitive) at angles of incidence resulting in local activation time differences shorter than unipolar downstroke duration. Directional sensitivity increases with closer electrode spacing, faster CV, and longer unipolar EGM duration. For narrowly spaced electrode pairs (<5 mm), it is predicted at all orientations. CONCLUSION: Directional sensitivity occurs because bipolar amplitude is reduced when the component unipolar EGMs overlap, such that neither electrode is "indifferent." At the electrode spacing of clinical catheters, this is predicted to occur regardless of catheter orientation. This suggests that bipolar directional sensitivity can be lessened but not overcome by recently introduced catheters with additional rotated electrode pairs.

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Published In

Heart Rhythm

DOI

EISSN

1556-3871

Publication Date

May 2020

Volume

17

Issue

5 Pt A

Start / End Page

777 / 785

Location

United States

Related Subject Headings

  • Middle Aged
  • Male
  • Humans
  • Heart Rate
  • Heart Conduction System
  • Heart Atria
  • Female
  • Electrophysiologic Techniques, Cardiac
  • Computer Simulation
  • Catheter Ablation
 

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Gaeta, S., Bahnson, T. D., & Henriquez, C. (2020). Mechanism and magnitude of bipolar electrogram directional sensitivity: Characterizing underlying determinants of bipolar amplitude. Heart Rhythm, 17(5 Pt A), 777–785. https://doi.org/10.1016/j.hrthm.2019.12.010
Gaeta, Stephen, Tristram D. Bahnson, and Craig Henriquez. “Mechanism and magnitude of bipolar electrogram directional sensitivity: Characterizing underlying determinants of bipolar amplitude.Heart Rhythm 17, no. 5 Pt A (May 2020): 777–85. https://doi.org/10.1016/j.hrthm.2019.12.010.
Gaeta, Stephen, et al. “Mechanism and magnitude of bipolar electrogram directional sensitivity: Characterizing underlying determinants of bipolar amplitude.Heart Rhythm, vol. 17, no. 5 Pt A, May 2020, pp. 777–85. Pubmed, doi:10.1016/j.hrthm.2019.12.010.
Journal cover image

Published In

Heart Rhythm

DOI

EISSN

1556-3871

Publication Date

May 2020

Volume

17

Issue

5 Pt A

Start / End Page

777 / 785

Location

United States

Related Subject Headings

  • Middle Aged
  • Male
  • Humans
  • Heart Rate
  • Heart Conduction System
  • Heart Atria
  • Female
  • Electrophysiologic Techniques, Cardiac
  • Computer Simulation
  • Catheter Ablation