title: Atrial septal angulation varies widely in patients undergoing pulmonary vein isolation.
abstract: OBJECTIVE
  Transseptal puncture (TSP) allows left atrial access for curative procedures. Intracardiac echocardiography (ICE) provides direct visualization of the interatrial septum (IAS), but adds time and expense. We reviewed 100 cardiac multidetector computed tomography (MDCT) scans of patients undergoing AF ablation to determine if the angulation and orientation of the IAS are conserved or variable. Significant variability may suggest a potential role for direct visualization of the IAS during TSP.
  
  
  METHODS
  We reviewed 100 MDCT scans obtained prior to AF ablation. The IAS plane at the fossa ovalis was identified in axial and coronal images. We measured the angle of the septum relative to an orthogonal plane. Optimal needle orientation was defined as perpendicular to the fossa ovalis.
  
  
  RESULTS
  The mean axial plane angle was -60.6 ± 10.6°; range, -29.5° to -88.7°). The mean coronal plane angle was 142.6 ± 9.1°; range, 115° to 162°). The axial angle corresponded to variation in the "clock-face" orientation of the needle during puncture, and was calculated between 4 and 6 o'clock. Coronal plane angulation corresponds to the curvature of the needle tip, which varied by 47°. We found no association between patient characteristics and IAS angle.
  
  
  CONCLUSIONS
  The septal orientation in the axial plane varied widely and was not predicted by clinical variables such as atrial size or prior valve surgery. The high degree of interpatient variability observed suggests that direct visualization of the septum may be helpful in the performance of TSP.
authors.affiliation: Knight Cardiovascular Institute, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland OR 97239 USA. henrikso@ohsu.edu.
authors.forename: Erin A
authors.initials: EA
authors.lastname: Fender
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Sibley
authors.forename: Saman
authors.initials: S
authors.lastname: Nazarian
authors.forename: Alan
authors.initials: A
authors.lastname: Cheng
authors.forename: David D
authors.initials: DD
authors.lastname: Spragg
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Marine
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Berger
authors.forename: Hugh
authors.initials: H
authors.lastname: Calkins
authors.forename: Joao A C
authors.initials: JA
authors.lastname: Lima
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Brinker
authors.forename: Charles A
authors.initials: CA
authors.lastname: Henrikson
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000601:surgery*; D054087:Atrial Septum / Q000000981:diagnostic imaging* / Q000601:surgery; D017115:Catheter Ablation; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D011667:Pulmonary Veins / Q000000981:diagnostic imaging / Q000601:surgery*; D011677:Punctures; D012189:Retrospective Studies; D016896:Treatment Outcome