title: Inadvertent atrioventricular block during radiofrequency catheter ablation. Results of the Pediatric Radiofrequency Ablation Registry. Pediatric Electrophysiology Society.
abstract: BACKGROUND
  Inadvertent atrioventricular block is a complication of radiofrequency ablation. The present study is an analysis of the incidence, significance, and factors associated with inadvertent atrioventricular block during radiofrequency catheter ablation in childhood and adolescence.
  
  
  RESULTS
  The records of the Pediatric Radiofrequency Ablation Registry were reviewed. Between January 1, 1991, and April 1, 1994, atrioventricular block occurred in 23 of 1964 radiofrequency ablations (1.2%): 14 as third-degree block (3 transient) and 9 as second-degree block (5 transient). Atrioventricular block occurred from 5 seconds to 2 months (mean, 4.1 days; median, 15 seconds) after the onset of the energy application. Eight transient cases lasted 1 hour to 1 month (mean, 9.4 days; median, 7 days). Inadvertent atrioventricular block was related to the ablation anatomic site: 3 of 111 (2.7%) anteroseptal, 11 of 106 (10.4%) midseptal, and 2 of 197 (1.0%) right posteroseptal sites (P = .0007) for anteroseptal, P = .0001 for midseptal, and P = .17 for right posteroseptal versus nonright septal sites). Five of 314 (1.6%) ablations for atrioventricular nodal reentrant tachycardia resulted in atrioventricular block (P = .004 versus nonright septal sites). Compared with a matched subgroup, radiofrequency ablation experience was the only significant risk factor (32.7 versus 106.6, P = .002) for the occurrence of atrioventricular block.
  
  
  CONCLUSIONS
  Inadvertent atrioventricular block may occur during or late after radiofrequency catheter ablation. It is associated with ablations for (1) anterior and midseptal accessory pathways and atrioventricular nodal reentry and (2) relative institutional inexperience.
authors.affiliation: Section of Cardiology, University of Colorado Medical School, Children's Hospital, Denver, USA. schaffer.michael@tchden.org
authors.forename: M S
authors.initials: MS
authors.lastname: Schaffer
authors.forename: M J
authors.initials: MJ
authors.lastname: Silka
authors.forename: B A
authors.initials: BA
authors.lastname: Ross
authors.forename: J D
authors.initials: JD
authors.lastname: Kugler
mesh_terms: D000293:Adolescent; D000328:Adult; D017115:Catheter Ablation / Q000009:adverse effects* / Q000379:methods; D002648:Child; D002675:Child, Preschool; D005500:Follow-Up Studies; D006327:Heart Block / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D006331:Heart Diseases / Q000145:classification / Q000601:surgery; D006801:Humans; D007223:Infant; D010138:Pacemaker, Artificial; D011183:Postoperative Complications / Q000453:epidemiology*; D012042:Registries; D013997:Time Factors; D016896:Treatment Outcome