title: His-Bundle Pacing for Identifying Optimal Ablation Sites in Patients Undergoing Atrioventricular Junction Ablation: Teaching an Old Dog a New Trick.
abstract: BACKGROUND
  Atrioventricular (AV) junction (AVJ) ablation is conventionally performed by localizing the His-bundle electrogram (HBE). Identification of HBE in the presence of atrial fibrillation (AF) can be difficult, and can make this simple procedure challenging. In this study, we describe our experience with an alternative approach to localize optimal ablation sites using His-bundle pacing (HBP).
  
  
  METHODS
  Between 1/1/2014 and 12/31/2015, we performed 13 AVJ ablations using the standard electrogram-guided approach and 11 ablations using HBP. All cases utilized a long femoral guiding sheath and an 8-mm-tip electrode radiofrequency (RF) energy ablation catheter. Pacing was performed at high output (10 mA at 2 ms) to initially achieve right bundle branch capture. The catheter was withdrawn until a narrow QRS morphology and increased stim-to-QRS time were observed. HBP was confirmed when paced and native QRS were identical in morphology. RF energy was applied at the site of HBP capture until AV block was observed.
  
  
  RESULTS
  Baseline characteristics of patients in each arm were not significantly different. Compared with the standard approach, HBP was associated with trends toward lower RF applications (3 vs. 2, P = 0.16) and shorter mean RF time (208 seconds vs. 128 seconds, P = 0.19).
  
  
  CONCLUSIONS
  HBP is an effective technique to identify optimal ablation sites during AVJ ablation and may shorten procedure time. HBP can be used to identify the AV node during AF without recording the His potential. Future studies with larger sample size are needed to better characterize the utility of this technique.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Nitin
authors.initials: N
authors.lastname: Kulkarni
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Curtiss
authors.initials: C
authors.lastname: Moore
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Ambarish
authors.initials: A
authors.lastname: Pandey
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Demetrio
authors.initials: D
authors.lastname: Castillo
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.|Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Colby
authors.initials: C
authors.lastname: Ayers
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Jose
authors.initials: J
authors.lastname: Joglar
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Richard
authors.initials: R
authors.lastname: Wu
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D001283:Atrioventricular Node / Q000601:surgery*; D018780:Body Surface Potential Mapping / Q000379:methods*; D002036:Bundle of His; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
keywords: AVJ junction ablation; AVN node ablation; atrial fibrillation; his-bundle pacing