title: Proximity of right coronary artery to cavotricuspid isthmus as determined by computed tomography.
abstract: BACKGROUND
  Radiofrequency ablation of atrial flutter is a commonly performed procedure. Ablation success depends upon complete transmural atrial tissue injury to achieve bidirectional cavotricuspid isthmus (CTI) block. Transmural ablation increases risk of injury to the adjacent right coronary artery (RCA). Distance between the RCA and the endocardium within the CTI area is not well described. We aimed to perform in vivo measurements of the distance between the CTI area and adjacent RCA.
  
  
  METHODS
  Thirty-three consecutive patients underwent electrocardiogram-gated contrast-enhanced computed tomography. CTI area was divided into nine segments based on three common catheter locations (paraseptal, central, and lateral or 5, 6, and 7 o'clock) and ventricular to atrial ablation line.
  
  
  RESULTS
  Mean age was 64 ± 11 years and 97% of the participants were male. Paraseptal, central, and lateral measurements at the tricuspid annulus ridge showed endocardial to RCA distance 9 ± 3, 6 ± 2, and 5 ± 3 mm, respectively (range 2-17 mm). Corresponding measurements for the ventricular side were 5 ± 3, 4 ± 2, and 4 ± 2 mm and atrial side measurements were 3 ± 2, 3 ± 2, and 3 ± 3 mm. Distance was ≤2 mm in 14% of segments on the ventricular side and 39% of segments on the atrial side. Paired t-test showed significant difference (P < 0.001) between tricuspid annulus ridge measurements and adjacent atrial or ventricular measurements.
  
  
  CONCLUSIONS
  Distance between endocardium and RCA lumen is reduced in areas adjacent to the tricuspid annulus ridge.
authors.affiliation: Division of Cardiology, Veterans Affairs Medical Center, University of Minnesota, Minneapolis, MN 55455, USA. alalo001@umn.edu
authors.forename: Basel
authors.initials: B
authors.lastname: Al Aloul
authors.forename: Gardar
authors.initials: G
authors.lastname: Sigurdsson
authors.forename: Ilknur
authors.initials: I
authors.lastname: Can
authors.forename: Jian-Mingi
authors.initials: JM
authors.lastname: Li
authors.forename: Richard
authors.initials: R
authors.lastname: Dykoski
authors.forename: Venkatakrishna N
authors.initials: VN
authors.lastname: Tholakanahalli
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000000981:diagnostic imaging / Q000601:surgery*; D003287:Contrast Media; D017023:Coronary Angiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014261:Tricuspid Valve / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000601:surgery; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging* / Q000601:surgery
chemical_list: D003287:Contrast Media