title: Ablation of focal atrial arrhythmia in patients with congenital heart defects after surgery: role of circumscribed areas with heterogeneous conduction.
abstract: BACKGROUND
  In patients late after surgical repair of congenital heart disease (CHD), areas with abnormal electrophysiologic properties may serve as slow conducting pathways within a macroreentrant circuit or may be the source of focal atrial tachycardia.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate the role of abnormal areas during focal atrial tachycardia prior to ablation.
  
  
  METHODS
  Electroanatomic activation mapping of 62 atrial tachycardias was performed in 43 consecutive patients (37 +/- 12 years) after surgical repair of CHD. The mechanism of atrial tachycardia was scar related intra-atrial reentry (n = 27), cavotricuspid-related atrial flutter (n = 21), atrial fibrillation (n = 2), or focal atrial tachycardia (n = 10). During intra-atrial reentry, channels of slow conduction could be identified in all patients. Subsequent ablation was directed toward connecting two nonconductive borders. The site of origin during focal atrial tachycardia showed fractionated potentials and/or continuous electrical activity.
  
  
  RESULTS
  Ablation directed at isolating the source area resulted in termination of focal atrial tachycardia in all cases. In two patients, ablation of an area showing continuous electrical activity giving rise to fibrillatory conduction resulted in termination of atrial fibrillation. Ablation of intra-atrial reentry was successful in 70%. Atrial flutter and focal atrial tachycardia were successfully ablated in all patients. No complications were observed.
  
  
  CONCLUSIONS
  In patients with surgically corrected CHD, atrial tachycardia most often is caused by a macroreentrant mechanism but in some is the result of a focal mechanism. Areas of abnormal conduction may serve not only as a zone of slow conduction within a macroreentrant circuit but also as the site of origin of a focal atrial arrhythmia. Catheter ablation directed at "source isolation" is effective in eliminating focal atrial tachycardia in patients with CHD.
authors.affiliation: Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Natasja M S
authors.initials: NM
authors.lastname: de Groot
authors.forename: Katja
authors.initials: K
authors.lastname: Zeppenfeld
authors.forename: Maurits C
authors.initials: MC
authors.lastname: Wijffels
authors.forename: Wing King
authors.initials: WK
authors.lastname: Chan
authors.forename: Nico A
authors.initials: NA
authors.lastname: Blom
authors.forename: Ernst E
authors.initials: EE
authors.lastname: Van der Wall
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schalij
mesh_terms: D000293:Adolescent; D000328:Adult; D001281:Atrial Fibrillation / Q000601:surgery; D001282:Atrial Flutter / Q000601:surgery; D018780:Body Surface Potential Mapping; D006348:Cardiac Surgical Procedures / Q000009:adverse effects; D017115:Catheter Ablation; D017097:Electric Impedance; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000473:pathology* / Q000503:physiopathology* / Q000601:surgery; D006330:Heart Defects, Congenital / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000601:surgery; D013612:Tachycardia, Ectopic Atrial / Q000601:surgery; D013617:Tachycardia, Supraventricular / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome