title: Atypical atrioventricular node reciprocating tachycardia masquerading as tachycardia using a left-sided accessory pathway.
abstract: OBJECTIVE
  The study was performed to document that atrioventricular node reciprocating tachycardia (AVNRT) can be associated with eccentric retrograde left-sided activation, masquerading as tachycardia using a left accessory pathway.
  
  
  BACKGROUND
  The eccentric retrograde left-sided activation during tachycardia is thought to be diagnostic of the presence of a left free wall accessory pathway. However, it is not known whether AVNRT can occur with eccentric retrograde left-sided activation.
  
  
  METHODS
  We studied 356 patients with AVNRT who underwent catheter ablation. Retrograde atrial activation during tachycardia and ventricular pacing were determined by intracardiac recordings, including the use of a decapolar coronary sinus catheter.
  
  
  RESULTS
  The retrograde atrial activation was eccentric in 20 patients (6%). Eight of these patients had the earliest retrograde atrial activation recorded in the lateral coronary sinus leads, and 12 had the earliest retrograde atrial activation recorded in the posterior coronary sinus leads, with the most proximal coronary sinus electrode pair straddling the coronary sinus orifice. These tachycardias were either the fast-slow or the slow-slow form of AVNRT. The slow-fast form of AVNRT was also inducible in 17 of the 20 patients. Successful ablation of the slow pathway in the right atrial septum near the coronary sinus ostium prevented the induction and clinical recurrence of reciprocating tachycardia in all patients.
  
  
  CONCLUSIONS
  Atypical AVNRT with eccentric retrograde left-sided activation was demonstrated in 6% of all patients with AVNRT masquerading as tachycardia using a left-sided accessory pathway. Ablation of the slow pathway at the posterior aspects of the right atrial septum resulted in a cure in these patients.
authors.affiliation: Central Utah Valley Medical Clinic, Utah Valley Cardiology, Provo 84604, USA.
authors.forename: C
authors.initials: C
authors.lastname: Hwang
authors.forename: D J
authors.initials: DJ
authors.lastname: Martin
authors.forename: J S
authors.initials: JS
authors.lastname: Goodman
authors.forename: E S
authors.initials: ES
authors.lastname: Gang
authors.forename: W J
authors.initials: WJ
authors.lastname: Mandel
authors.forename: C D
authors.initials: CD
authors.lastname: Swerdlow
authors.forename: C T
authors.initials: CT
authors.lastname: Peter
authors.forename: P S
authors.initials: PS
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D017115:Catheter Ablation; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System; D006801:Humans; D008297:Male; D008875:Middle Aged; D013610:Tachycardia / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis* / Q000503:physiopathology* / Q000628:therapy