title: Evaluation of left atrial and posterior mediastinal anatomy by multidetector helical computed tomography imaging: relevance to ablation.
abstract: BACKGROUND
  Increasing use of catheter ablation in the left atrium (LA) requires understanding of substrate anatomy, especially with regard to potential damage to adjacent structures.
  
  
  RESULTS
  We reviewed multidetector helical computed tomography (MDCT) imaging on 42 subjects, 26 imaged before planned LA ablation for atrial fibrillation (AF), and 16 without AF. LA volume and dimensions were larger in patients with AF (p < 0.05) and the spine and aorta (Ao) impressed the LA more frequently in the AF group. The esophagus (Eo) was the predominant feature on the posterior LA wall, contacting it in all patients. The Ao was in contact with the LA body or the left inferior pulmonary vein (PV) in 32 (76%) of 42 cases, and in 10 it ran along an indentation on the posterior aspect of the LA. The coronary sinus was adjacent to LA ablation sites, the azygos vein was rarely adjacent to those sites, and the left bronchus abutted the PV ostium but not the LA. Two patients had findings that directly impacted the ablation procedure: one patient had a dilated fluid filled Eo with esophageal stricture and underwent nasogastric decompression before ablation, and one was discovered to have an anomalous PV and underwent surgical repair.
  
  
  CONCLUSIONS
  MDCT imaging identifies structures adjacent to the LA, which could be affected by ablation. Posterior LA topography can be influenced by the position of the Ao or by the proximity of the spine. Preprocedural imaging can characterize anatomic structures that could be vulnerable during ablation, and detect unusual pathology that can affect the treatment plan.
authors.affiliation: Division of Cardiac Electrophysiology, Department of Radiology, Caritas Saint Elizabeth's Medical Center, Tufts University School of Medicine, Boston, MA 02135, USA. p_hoffmeister@yahoo.com
authors.forename: Peter S
authors.initials: PS
authors.lastname: Hoffmeister
authors.forename: G Muqtada
authors.initials: GM
authors.lastname: Chaudhry
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Mendel
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Almasry
authors.forename: Syed
authors.initials: S
authors.lastname: Tahir
authors.forename: Thomas
authors.initials: T
authors.lastname: Marchese
authors.forename: Charles I
authors.initials: CI
authors.lastname: Haffajee
authors.forename: Michael V
authors.initials: MV
authors.lastname: Orlov
mesh_terms: D000328:Adult; D000368:Aged; D001027:Aortography; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging* / Q000601:surgery; D017115:Catheter Ablation; D004947:Esophagus / Q000000981:diagnostic imaging; D005260:Female; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008482:Mediastinum / Q000000981:diagnostic imaging*; D008875:Middle Aged; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D036542:Tomography, Spiral Computed