title: Effect of Left Atrial Wall Thickness on Radiofrequency Ablation Success.
abstract: BACKGROUND
  Radiofrequency (RF) ablation in thicker regions of the left atrium (LA) may require increased ablation energy in order to achieve effective transmural lesions. Consequently, many cases of recurrent atrial fibrillation (AF) postablation may be due to thicker-than-normal atrial tissue. The aim of this study was to test the hypotheses that patients with recurrent AF have thicker tissue overall and that electrical reconnection is more likely in regions of thicker tissue.
  
  
  RESULTS
  Retrospective analysis was performed on 86 CT images acquired preoperatively from a cohort of 119 patients who had undergone RF ablation for AF. Of these, 33 patients experienced recurrence of AF within 1 year of initial treatment and 29 returned for a repeat ablation. For each patient, LA wall thickness (LAWT) was measured from the images in 12 anatomical regions using custom software. Patients with recurrent AF had larger LAWT compared to successfully treated patients (1.6 ± 0.6 mm vs. 1.5 ± 0.5 mm, P < 0.001) and reconnection was found to be at regions of thicker tissue (1.6 ± 0.6 mm, P = 0.038) compared to nonreconnected regions (1.5 ± 0.5 mm). The superior right posterior wall of the LA was significantly related to both recurrence (P = 0.048) and reconnection (P = 0.014).
  
  
  CONCLUSIONS
  Increased LAWT has a small but significant effect on postablation recurrence and reconnection. Measures of LAWT may facilitate appropriate dosing of RF energy, but other factors will be critical in transmural lesion formation and ablation success.
authors: Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.
authors: Jiro
authors: J
authors: Inoue
authors: Division of Cardiology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada.
authors: Allan C
authors: AC
authors: Skanes
authors: Division of Cardiology, Department of Medicine, The University of Western Ontario, London, Ontario, Canada.
authors: Lorne J
authors: LJ
authors: Gula
authors: Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada.|Department of Medical Biophysics, The University of Western Ontario, London, Ontario, Canada.
authors: Maria
authors: M
authors: Drangova
keywords: CT scan; atrial fibrillation; electrical reconnection; left atrium; radiofrequency catheter ablation; wall thickness