title: Electroanatomic mapping of entrained and exit zones in patients with repaired congenital heart disease and intra-atrial reentrant tachycardia.
abstract: BACKGROUND
  Characterization of reentrant circuits and targeting ablation sites remains difficult for intra-atrial reentrant tachycardias (IART) in congenital heart disease (CHD).
  
  
  RESULTS
  Electroanatomic mapping and entrainment pacing were performed before successful ablation of 18 IART circuits in 15 patients with CHD. Principal features of IART circuits were atrial septal defect (4 patients), atriotomy (3 patients), other atrial scar (3 patients), crista terminalis (3 patients), and right atrioventricular valve (5 patients). A median of 176 sites (range, 96 to 317 sites) was mapped for activation and 13 sites (range, 9 to 28 sites) for entrainment response. Postpacing intervals within 20 ms of tachycardia cycle length and stimulus-to-P-wave intervals of 0 to 90 ms (exit zones) were mapped to atrial surfaces generated by electroanatomic mapping. Criteria for entrainment were met over a median of 21 cm2 of atrial surface (range, 2 to 75 cm2), 19% (range, 1% to 81%) of total area tested. Using integrated data, relations between activation sequence and protected corridor of conduction could be inferred for 16 of 17 LARTs. Successful ablation was achieved at a site distant from the putative protected corridor in 9 of 18 (50%) circuits.
  
  
  CONCLUSIONS
  The right atrium in CHD supports a variety of IART mechanisms. Fusion of activation and entrainment data provided insight into specific IART mechanisms relevant to ablation.
authors.affiliation: Department of Cardiology, Children's Hospital, Boston, MA 02115, USA. triedman@cardio1.tch.harvard.edu
authors.forename: J K
authors.initials: JK
authors.lastname: Triedman
authors.forename: M E
authors.initials: ME
authors.lastname: Alexander
authors.forename: C I
authors.initials: CI
authors.lastname: Berul
authors.forename: L M
authors.initials: LM
authors.lastname: Bevilacqua
authors.forename: E P
authors.initials: EP
authors.lastname: Walsh
mesh_terms: D000293:Adolescent; D000328:Adult; D001282:Atrial Flutter / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D018780:Body Surface Potential Mapping; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D002648:Child; D002675:Child, Preschool; D003952:Diagnostic Imaging; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006325:Heart Atria / Q000503:physiopathology* / Q000601:surgery; D006330:Heart Defects, Congenital / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013610:Tachycardia / Q000175:diagnosis* / Q000503:physiopathology* / Q000601:surgery; D016896:Treatment Outcome