title: Dual-loop intra-atrial reentry in humans.
abstract: BACKGROUND
  Dual-loop atrial reentrant tachycardias have not been clinically described.
  
  
  RESULTS
  Five patients (3 men, 2 women; mean age, 48+/-16 years) were studied 24+/-15 years after surgical closure of an ostium secundum atrial septal defect for drug-resistant atrial tachycardia. Complete tachycardia mapping was performed in the right atrium with multipolar catheters and a 3-dimensional electroanatomic mapping system (Biosense), followed by linear radiofrequency ablation of the narrowest part of each complete loop. Six tachycardias with a typical flutter morphology, a cycle length of 262+/-40 ms, and a superior f-wave axis (-77+/-11 degrees ) were mapped, 4 with a Biosense map including 106+/-32 points. Five figure-8 tachycardias had a counterclockwise loop around the tricuspid valve sharing a common anterior channel with a clockwise loop around the lateral atriotomy scar. One tachycardia was thought to have 2 counterclockwise loops around the same obstacles. Radiofrequency delivery in the cavotricuspid isthmus in each case transformed the tachycardia without any pause in a different morphology tachycardia with an inferior P-wave axis (50+/-42 degrees ) and nearly the same cycle length (272+/-39 ms) but with the periatriotomy loop alone. This arrhythmia required ablation of a second isthmus: between the lower end of the atriotomy and the inferior vena cava in 4 and the superior tricuspid annulus in 1. After a follow-up of 19+/-6 months, there were no recurrences.
  
  
  CONCLUSIONS
  Figure-8 double-loop tachycardias mimicking the ECG pattern of a common atrial flutter occur in some patients after a surgical atriotomy. Ablation of 1 loop produces a sudden transformation to a new reentrant tachycardia formed of the remaining loop that requires ablation at a second isthmus.
authors.affiliation: Department de Rhythmologie, Hôpital Cardiologique du Haut-Lévêque, Bordeaux-Pessac, France.
authors.forename: D
authors.initials: D
authors.lastname: Shah
authors.forename: P
authors.initials: P
authors.lastname: Jaïs
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Hocini
authors.forename: J T
authors.initials: JT
authors.lastname: Peng
authors.forename: J
authors.initials: J
authors.lastname: Clementy
authors.forename: M
authors.initials: M
authors.lastname: Haïssaguerre
mesh_terms: D000328:Adult; D001282:Atrial Flutter / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006344:Heart Septal Defects, Atrial / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged