title: Comparison of anatomic isthmus block with the modified right atrial maze procedure for late atrial tachycardia in Fontan patients.
abstract: BACKGROUND
  Late atrial reentry tachycardia (AT) after Fontan repair is common, with limited efficacy of medical therapy in preventing AT recurrence. In this study, two approaches to surgical arrhythmia ablation in patients with refractory AT undergoing Fontan revision are compared: cryoablation of the inferomedial right atrium (RA), and a more extensive modified RA maze procedure designed to eliminate all potential RA reentrant circuits.
  
  
  RESULTS
  Fontan revision was performed in 23 patients with AT, using inferomedial RA cryoablation (Group 1, n=8) and modified RA maze procedure (Group 2, n=15). There was no difference in age at initial Fontan, age at Fontan revision, age at onset of AT, or number of failed antiarrhythmic medications. Patients underwent preoperative, intraoperative, and postoperative electrophysiological studies. Thirty-eight different tachycardia circuits were induced in preoperative studies with 3 major areas of RA involvement: the lower lateral RA, the atrial septum, and the inferomedial RA. At postoperative electrophysiological study, AT was inducible in 62% of Group 1 patients but only 7% of Group 2 patients (P<0.02). With mean follow-up of 43 months, 5 of 8 patients in Group 1 experienced AT recurrence compared with none in Group 2 (P<0.001). There was no significant difference in length of hospital stay or complication rate comparing the two groups.
  
  
  CONCLUSIONS
  Modified RA maze procedure is superior to anatomic isthmus block in treating reentrant AT in postoperative Fontan patients. The modified RA maze has eliminated AT recurrence at mid-term follow-up with low morbidity and mortality.
authors.affiliation: Division of Cardiology, Children's Memorial Hospital, Chicago, IL 60614, USA. bdeal@northwestern.edu
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Deal
authors.forename: Constantine
authors.initials: C
authors.lastname: Mavroudis
authors.forename: Carl L
authors.initials: CL
authors.lastname: Backer
authors.forename: Scott H
authors.initials: SH
authors.lastname: Buck
authors.forename: Christopher
authors.initials: C
authors.lastname: Johnsrude
mesh_terms: D000293:Adolescent; D018780:Body Surface Potential Mapping; D006348:Cardiac Surgical Procedures / Q000379:methods*; D002648:Child; D003452:Cryosurgery; D017147:Defibrillators, Implantable; D022062:Electrophysiologic Techniques, Cardiac; D005500:Follow-Up Studies; D018729:Fontan Procedure / Q000009:adverse effects*; D006325:Heart Atria / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D010138:Pacemaker, Artificial; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D013610:Tachycardia / Q000209:etiology* / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome