title: Left atrial wall thickness variability measured by CT scans in patients undergoing pulmonary vein isolation.
abstract: BACKGROUND
  Successful catheter ablation of atrial fibrillation (AF) requires the creation of transmural lesions in the left atrium (LA). In addition, cardiac perforation is more likely to occur in areas of thin walls. The LA wall thickness is thus relevant both for procedural efficacy and safety. This study sought to evaluate the regional LA wall thickness in patients with AF.
  
  
  METHODS
  The LA muscular wall thickness (excluding fat) was measured by 64 slice cardiac computed tomography (CT) in 60 patients with persistent AF prior to catheter ablation procedures. Measurements were performed in all patients at 12 distinct LA locations, including 3 at the roof (right, middle left), 3 at the floor (right, middle, left), 4 at the posterior wall (right, middle, middle-superior, left), 1 at the left lateral ridge (LLR), and 1 at the mitral isthmus.
  
  
  RESULTS
  There was a large range of LA wall thickness (average thickness 1.89 ± 0.48 mm, range 0.5-3.5 mm). In addition, there were significant regional differences in LA wall thickness. In particular, the LA roof was significantly thicker than the posterior wall and floor (P < 0.001), the LLR was significantly thicker than most regions (P < 0.04), and the mitral isthmus was also significantly thicker than the posterior wall (P < 0.001) and floor (P < 0.001).
  
  
  CONCLUSIONS
  In patients with persistent AF, there is inter- and intra-patient variability in the thickness of the LA muscular wall. In most patients, however, the roof, mitral isthmus, and the ridge between the pulmonary veins and appendage are thicker compared to the posterior wall and floor.
authors: From the Heart Center, Massachusetts General Hospital, Boston, Massachusetts, USA.
authors: Roy
authors: R
authors: Beinart
authors: Suhny
authors: S
authors: Abbara
authors: Andrew
authors: A
authors: Blum
authors: Maros
authors: M
authors: Ferencik
authors: Kevin
authors: K
authors: Heist
authors: Jeremy
authors: J
authors: Ruskin
authors: Moussa
authors: M
authors: Mansour