title: Isthmus-dependent right atrial flutter as the leading cause of atrial tachycardias after surgical atrial septal defect repair.
abstract: OBJECTIVE
  The purpose of this study was to evaluate clinical and electrophysiologic characteristics of AT in patients after surgical ASD repair as well as outcome after ablation.
  
  
  BACKGROUND
  Atrial tachycardias (AT) are a common complication after surgical closure of an atrial septal defect (ASD).
  
  
  METHODS
  From a prospective ablation database we analyzed data of patients with a history of ASD repair who presented to our institution for AT ablation. We investigated ECG characteristics and the electrophysiologic mechanism of AT in this collective and analyzed follow-up data.
  
  
  RESULTS
  Data of 54 patients (47.3 ± 14.5 years, 35 females) were included. In 30 patients (55.6%) ASD had been closed by direct suture, 24 patients (44.4%) had a patch for ASD repair without significant difference in terms of gender and age at the time of the procedure (p=0.234, p=0.231). In 42 patients (77.8%), electrophysiological studies were performed in AT. All patients had right atrial macro-reentrant AT. The leading mechanism was isthmus-dependent right atrial flutter in 29 patients (69.0%) with clockwise atrial activation in 41%. The mechanism of AT (typical atrial flutter (n=29), atriotomy-dependent flutter (n=7), and double loop flutter (n=5)) did not differ with regard to type of surgery. Only 70.6% of patients with proven isthmus dependent counter-clockwise atrial flutter presented with an ECG morphology typical for this mechanism. However, all clockwise typical atrial flutter patients showed the characteristic positive P-waves in the inferior leads. Of note, 83.3% of clockwise typical flutter ECGs had long isoelectric lines (mean 74.5 ms). Follow-up was complete in 45 of 54 patients. During a mean follow-up of 7.7 ± 3.7 years, 27 patients (60%) remained free of any arrhythmia, two patients had AT recurrence with different mechanisms compared to the first procedure and underwent successful ablation. Five patients (11%) developed atrial fibrillation.
  
  
  CONCLUSIONS
  Isthmus dependent right atrial flutter is the leading AT mechanism in patients with a history of ASD repair. The mechanism of atrial flutter did not differ in relation to the mode of ASD closure (direct suture versus patch closure). ECG characteristics of the tachycardia may be misleading as they are more often atypical in patients after ASD repair.
authors.affiliation: Division of Electrophysiology, Department of Cardiovascular Medicine, University Hospital Münster, Germany. Electronic address: wasmerk@ukmuenster.de.
authors.forename: Kristina
authors.initials: K
authors.lastname: Wasmer
authors.forename: Julia
authors.initials: J
authors.lastname: Köbe
authors.forename: Dirk G
authors.initials: DG
authors.lastname: Dechering
authors.forename: Alex
authors.initials: A
authors.lastname: Bittner
authors.forename: Gerold
authors.initials: G
authors.lastname: Mönnig
authors.forename: Peter
authors.initials: P
authors.lastname: Milberg
authors.forename: Helmut
authors.initials: H
authors.lastname: Baumgartner
authors.forename: Günter
authors.initials: G
authors.lastname: Breithardt
authors.forename: Lars
authors.initials: L
authors.lastname: Eckardt
mesh_terms: D000328:Adult; D000368:Aged; D001282:Atrial Flutter / Q000150:complications*; D017115:Catheter Ablation; D005260:Female; D006325:Heart Atria; D006344:Heart Septal Defects, Atrial / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology*; D011446:Prospective Studies; D013610:Tachycardia / Q000209:etiology*
keywords: Ablation; Atrial flutter; Atrial septal defect repair