title: Anterograde conduction to the His bundle during right ventricular overdrive pacing distinguishes septal pathway atrioventricular reentry from atypical atrioventricular nodal reentrant tachycardia.
abstract: BACKGROUND
  Distinguishing orthodromic atrioventricular reciprocating tachycardia (ORT) using a retrograde septal accessory pathway (AP) from atypical atrioventricular nodal reentrant tachycardia (AVNRT) may be challenging. Specifically, excluding the presence and participation of an AP may require multiple diagnostic maneuvers.
  
  
  OBJECTIVE
  The purpose of this study was to assess the relative value of commonly used right ventricular (RV) pacing maneuvers, including identification of anterograde His-bundle activation with entrainment, to differentiate ORT using a retrograde septal AP from atypical AVNRT.
  
  
  METHODS
  From March 2009 to June 2014, 56 patients (28 female; age 43.9 ± 17.4 years) who underwent electrophysiologic study and ablation for supraventricular tachycardia (26 ORT using septal AP and 30 atypical AVNRT) that exhibited a concentric atrial activation pattern and a septal ventriculoatrial interval >70 ms were analyzed.
  
  
  RESULTS
  Overdrive pacing maneuvers or ventricular extrastimuli failed on at least 1 occasion to correctly identify a septal AP. Overall, 16 ORT patients and 26 AVNRT patients had successful RV entrainment, and 12 (75%) ORT patients showed anterograde His capture (11 patients) and/or anterograde septal ventricular capture (3 patients). None of the patients with atypical AVNRT showed anterograde conduction to the His bundle with entrainment.
  
  
  CONCLUSIONS
  RV pacing maneuvers are useful to exclude an AP in patients with AVNRT having concentric atrial activation sequence and a septal ventriculoatrial interval >70 ms; however, none are consistently diagnostic. When observed in this patient population, anterograde His-bundle or septal ventricular capture during RV entrainment was diagnostic for ORT using a septal AP.
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Koichi
authors.initials: K
authors.lastname: Nagashima
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: William G
authors.initials: WG
authors.lastname: Stevenson
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Laurence M
authors.initials: LM
authors.lastname: Epstein
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Roy M
authors.initials: RM
authors.lastname: John
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Usha B
authors.initials: UB
authors.lastname: Tedrow
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Koplan
authors.affiliation: Arrhythmia Unit, Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts. Electronic address: gfmichaud@partners.org.
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Michaud
mesh_terms: D000328:Adult; D002036:Bundle of His / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006329:Heart Conduction System / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D054088:Ventricular Septum / Q000503:physiopathology*
keywords: Accessory pathway; Anterograde His capture; Atrioventricular nodal tachycardia; Constant fusion; Entrainment; Orthodromic reciprocating tachycardia; Supraventricular tachycardia