Atrial fibrillation propagates through gaps in ablation lines: Implications for ablative treatment of atrial fibrillation

Spencer J. Melby, Anson M. Lee, Andreas Zierer, Scott P. Kaiser, Masha J. Livhits, John P. Boineau, Richard B. Schuessler, Ralph J. Damiano

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

Background: It has been hypothesized that atrial lesions must be transmural to successfully cure atrial fibrillation (AF). However, ablation lines often do not extend completely across the atrial wall. Objective: The purpose of this study was to determine the effect of residual gaps on conduction properties of atrial tissue. Methods: Canine right atria (n = 13) were isolated, perfused, and mounted on a 250-lead electrode plaque. The atria were divided with a bipolar radiofrequency ablation clamp, leaving a gap that was progressively narrowed. Conduction velocities at varying pacing rates and AF frequencies were measured before and after ablations. AF was induced with an extra stimulus and acetylcholine. Results: Gap widths from 11.2 to 1.1 mm were examined. Conduction velocities through gaps were dependent cycle length (P = .002) and gap size (P <.001). Overall, 253 (97%) of a total of 260 gaps allowed paced propagation; 51 (91%) of 56 gaps 1-3 mm in width permitted paced propagation, as did 202 (99%) of 204 gaps ≥3.0 mm. Similarly, 253 (97%) of a total of 260 gaps allowed propagation of AF. For AF, 51 (93%) of 55 gaps 1-3 mm allowed AF to pass through, as did 202 (99%) of 205 gaps ≥3.0 mm. Gaps as small as 1.1 mm conducted paced and AF impulses. Conclusions: Conduction velocities were slowed through residual gaps. However, propagation of wave fronts during pacing and AF occurred through the majority of residual gaps, down to sizes as small as 1.1 mm. Leaving viable tissue in ablation lines for the treatment of AF could account for failures.

Original languageEnglish
Pages (from-to)1296-1301
Number of pages6
JournalHeart rhythm
Volume5
Issue number9
DOIs
StatePublished - Sep 2008

Keywords

  • Ablation gap
  • Atrial fibrillation
  • Radiofrequency ablation
  • Transmural

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