title: Characterization of reentrant circuit in macroreentrant right atrial tachycardia after surgical repair of congenital heart disease: isolated channels between scars allow "focal" ablation.
abstract: BACKGROUND
  The purpose of this study was to characterize the circuit of macroreentrant right atrial tachycardia (MacroAT) in patients after surgical repair of congenital heart disease (SR-CHD).
  
  
  RESULTS
  Sixteen patients with atrial tachycardia (AT) after SR-CHD were studied (atrial septal defect in 6, tetralogy of Fallot in 4, and Fontan procedure in 6). Electroanatomic right atrial maps were obtained during 15 MacroATs in 13 patients, focal AT in 1 patient, and atrial pacing in 2 patients without stable AT. A large area of low bipolar voltage (</=0.5 mV) involved most of the free wall in all patients and contained 2 to 7 dense scars or lines of double potentials, forming 29 narrow channels (width </=2.7 cm) between scars in all but 1 patient, who had a single scar and only focal AT. All 15 MacroATs were propagated through narrow channels. Ablation within the channel eliminated all 15 MacroATs with 1 to 3 (median 1) radiofrequency applications. Ablation was performed in 9 other channels identified during MacroAT (5 patients) and in 5 channels identified during atrial pacing (2 patients). Conduction block was obtained across 28 of 29 channels. After ablation, reproducible sustained right AT was not induced in any patient. During follow-up (median 13.5 months), new MacroATs, atrial fibrillation, or palpitations occurred in 3 of 16 patients.
  
  
  CONCLUSIONS
  MacroAT after SR-CHD requires a large area of low voltage containing >/=2 scars forming narrow channels. Ablation within the channels eliminates MacroAT.
authors.affiliation: Cardiac Arrhythmia Research Institute, University of Oklahoma Health Sciences Center, Oklahoma City, USA. hiroshi-nakagawa@ouhsc.edu
authors.forename: H
authors.initials: H
authors.lastname: Nakagawa
authors.forename: N
authors.initials: N
authors.lastname: Shah
authors.forename: K
authors.initials: K
authors.lastname: Matsudaira
authors.forename: E
authors.initials: E
authors.lastname: Overholt
authors.forename: K
authors.initials: K
authors.lastname: Chandrasekaran
authors.forename: K J
authors.initials: KJ
authors.lastname: Beckman
authors.forename: P
authors.initials: P
authors.lastname: Spector
authors.forename: J D
authors.initials: JD
authors.lastname: Calame
authors.forename: A
authors.initials: A
authors.lastname: Rao
authors.forename: C
authors.initials: C
authors.lastname: Hasdemir
authors.forename: K
authors.initials: K
authors.lastname: Otomo
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: R
authors.initials: R
authors.lastname: Lazzara
authors.forename: W M
authors.initials: WM
authors.lastname: Jackman
mesh_terms: D000328:Adult; D001282:Atrial Flutter; D016280:Atrial Function, Right; D017115:Catheter Ablation; D004594:Electrophysiology; D005260:Female; D005500:Follow-Up Studies; D018729:Fontan Procedure; D006344:Heart Septal Defects, Atrial / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery