title: Atypical atrioventricular nodal reentry tachycardia with atrioventricular block mimicking atrial tachycardia: electrophysiologic properties and radiofrequency ablation therapy.
abstract: BACKGROUND
  Fast-intermediate form AV nodal reentry tachycardia (AVNRT) sometimes may mimic atrial tachycardia or atrial flutter and render the diagnosis difficult when the tachycardia rate is fast and AV block occurs during tachycardia.
  
  
  RESULTS
  A 45-year-old woman with paroxysmal supraventricular tachycardia was referred to this institution. Initially, the tachycardia was thought to be an atrial tachycardia because of: (1) a short cycle length of the tachycardia with 2:1 and Wenckebach AV block; (2) a difference in the atrial activation sequence during tachycardia and during ventricular pacing; and (3) failure of burst ventricular pacing to affect the atrial rate and the atrial activation sequence during tachycardia. An accurate diagnosis of fast-intermediate form AVNRT was subsequently made based on the finding that the tachycardia was induced following delivery of a third ventricular extrastimulus, which showed a sequence of V-A-H and a change on atrial activation sequence of the induced beat. Successful radiofrequency ablation was achieved only after accurate diagnosis of the tachycardia was made.
  
  
  CONCLUSIONS
  Fast-intermediate form AVNRT sometimes may masquerade as atrial tachycardia. Accurate diagnosis is mandatory for successful ablation therapy.
authors.affiliation: Department of Medicine, Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Taipei, Taiwan.
authors.forename: Y
authors.initials: Y
authors.lastname: Taniguchi
authors.forename: S J
authors.initials: SJ
authors.lastname: Yeh
authors.forename: M S
authors.initials: MS
authors.lastname: Wen
authors.forename: C C
authors.initials: CC
authors.lastname: Wang
authors.forename: D
authors.initials: D
authors.lastname: Wu
mesh_terms: D017115:Catheter Ablation; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008875:Middle Aged; D013610:Tachycardia / Q000503:physiopathology* / Q000601:surgery; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000503:physiopathology* / Q000601:surgery