title: Just how stable are escape rhythms after atrioventricular junction ablation?
abstract: BACKGROUND
  Atrioventricular (AV) node ablation with implantation of a permanent pacemaker is an established mode of therapy in the treatment of atrial fibrillation. However, concern exists regarding subsequent dependency on an entirely paced rhythm and the possible sequela of unheralded pacemaker failure. Data regarding escape rhythm lability, an important feature of pacemaker dependency, are limited.
  
  
  OBJECTIVE
  The purpose of this study was twofold: (1) to determine the characteristics of escape rhythms at predefined serial time intervals following AV node ablation and pacemaker implantation, and (2) to identify risk factors predictive of unstable escape rhythms. Patients undergoing AV node ablation and pacemaker implantation were assessed for the presence or absence of an escape rhythm during pacemaker interrogation at five predetermined serial time points. Baseline demographics and comorbid conditions were evaluated as potential predictors of those with labile escape rhythms.
  
  
  RESULTS
  Seventy-nine percent of the 96 patients studied had an underlying escape rhythm (> or =30 beats per minute) immediately postablation. Although the percentage of patients with an escape rhythm increased at each follow-up interval, the number of patients who consistently demonstrated an escape rhythm declined with each follow-up, with 28% of patients lacking an escape rhythm at some time point, i.e., labile escape rhythm. There were no significant predictors of a labile escape rhythm.
  
  
  CONCLUSIONS
  Among patients who have undergone AV node ablation and pacemaker implantation, 72% have a stable escape rhythm over time, but others are at risk for pacemaker dependency, as predicted by an underlying absent or labile escape rhythm.
authors.affiliation: Northwestern University-Feinberg School of Medicine, Chicago, Illinois, USA.
authors.forename: Rishi
authors.initials: R
authors.lastname: Arora
authors.forename: Erica
authors.initials: E
authors.lastname: Spatz
authors.forename: Pugazhendhi
authors.initials: P
authors.lastname: Vijayaraman
authors.forename: Michael
authors.initials: M
authors.lastname: Rosengarten
authors.forename: Jay
authors.initials: J
authors.lastname: Gross
authors.forename: Soo
authors.initials: S
authors.lastname: Kim
authors.forename: John
authors.initials: J
authors.lastname: Fisher
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Ferrick
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000601:surgery* / Q000628:therapy; D001283:Atrioventricular Node / Q000601:surgery*; D017115:Catheter Ablation; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012307:Risk Factors