Time course and mechanisms of endo-epicardial electrical dissociation during atrial fibrillation in the goat

Jens Eckstein*, Bart Maesen, Dominik Linz, Stef Zeemering, Arne van Hunnik, Sander Verheule, Maurits Allessie, Ulrich Schotten

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

100 Citations (Web of Science)

Abstract

Aims This study aims to determine the degree and mechanisms of endo-epicardial dissociation of electrical activity during atrial fibrillation (AF) and endo-epicardial differences in atrial electrophysiology at different stages of atrial remodelling. Methods and results Simultaneous high-density endo-epicardial mapping of AF was performed on left atrial free walls of goats with acute AF, after 3 weeks, and after 6 months of AF (all n = 7). Endo-epicardial activation time differences and differences in the direction of conduction vectors were calculated, endocardial and epicardial effective refractory periods (ERP) were determined, and fractionation of electrograms was quantified. Histograms of endo-epicardial activation time differences and differences in the direction of conduction vectors revealed two distinct populations, i.e. dissociated and non-dissociated activity. Dyssynchronous activity (dissociated in time) increased from 17 +/- 7% during acute AF to 39 +/- 17% after 3 weeks, and 68 +/- 13% after 6 months of AF. Dissociation was more pronounced in thicker parts of the atrial wall (thick: 49.3 +/- 21.4%, thin: 42.2 +/- 19.0%, P, <0.05). At baseline, endocardial ERPs were longer when compared with epicardial ERPs (DERP, 21.8 +/- 18 ms; P, <0.001). This difference was absent after 6 months of AF. The percentage of fractionated electrograms during rapid pacing increased from 9.4 +/- 1.9% ( baseline) to 18.6 +/- 0.6% (6 months). Conclusion During AF, pronounced dissociation of electrical activity occurs between the epicardial layer and the endocardial bundle network. The increase in dissociation is due to owing to progressive uncoupling between the epicardial layer and the endocardial bundles and correlates with increasing stability and complexity of the AF substrate.
Original languageEnglish
Pages (from-to)816-824
JournalCardiovascular Research
Volume89
Issue number4
DOIs
Publication statusPublished - Mar 2011

Keywords

  • Atrial fibrillation
  • Conduction
  • Endo-epicardial mapping
  • Dissociation
  • Remodelling

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