title: Mechanism of atrial flutter occurring late after orthotopic heart transplantation with atrio-atrial anastomosis.
abstract: OBJECTIVE
  We sought to better define the electrophysiologic mechanism of atrial flutter in patients after heart transplantation.
  
  
  BACKGROUND
  Atrial flutter is a recognized problem in the post-cardiac transplant population. The electrophysiologic basis of atrial flutter in this patient population is not completely understood.
  
  
  METHODS
  Six patients with cardiac allografts and symptoms related to recurrent atrial flutter underwent diagnostic electrophysiologic study with electroanatomic mapping and radiofrequency catheter ablation. Comparison was made with a control non-transplant population of 11 patients with typical counterclockwise right atrial flutter.
  
  
  RESULTS
  In each case, mapping showed typical counterclockwise activation of the donor-derived portion of the right atrium, with concealed entrainment shown upon pacing in the cavotricuspid isthmus (CTI). The anastomotic suture line of the atrio-atrial anastomosis formed the posterior barrier of the reentrant circuit. Ablation of the electrically active, donor-derived portion of the CTI was sufficient to terminate atrial flutter and render it noninducible. Comparison with the control population showed that the electrically active portion of the CTI was significantly shorter in patients with transplant-associated flutter and that ablation was accomplished with the same or fewer radiofrequency lesions.
  
  
  CONCLUSIONS
  Atrial flutter in cardiac transplant recipients is a form of typical counterclockwise, isthmus-dependent flutter in which the atrio-atrial anastomotic suture line forms the posterior barrier of the reentrant circuit. Ablation in the donor-derived portion of the CTI is sufficient to create bidirectional conduction block and eliminate this arrhythmia. Ablation or surgical division of the donor CTI at the time of transplantation could prevent this arrhythmia.
authors.affiliation: Henry Ford Heart and Vascular Institute, Detroit, Michigan 48202, USA.
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Marine
authors.forename: Claudio D
authors.initials: CD
authors.lastname: Schuger
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
authors.forename: Gautham
authors.initials: G
authors.lastname: Kalahasty
authors.forename: Fabian
authors.initials: F
authors.lastname: Arnaldo
authors.forename: Barbara
authors.initials: B
authors.lastname: Czerska
authors.forename: Subramaniam C
authors.initials: SC
authors.lastname: Krishnan
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000209:etiology* / Q000503:physiopathology; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000601:surgery*; D016027:Heart Transplantation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications