title: Antazoline for rapid termination of atrial fibrillation during ablation of accessory pathways.
abstract: OBJECTIVE
  To assess safety and efficacy of antazoline for termination of atrial fibrillation (AF) occurring during ablation of accessory pathways (AP).
  
  
  METHODS
  We analyzed electrophysiological mechanism of antazoline (changes in A-A interval) and the percentage of pre-excited QRS complexes before and after antazoline administration. The total dose administered and the time from the start of injection to sinus rhythm restoration were also measured.
  
  
  RESULTS
  Out of consecutive 290 patients with Wolff-Parkinson-White syndrome undergoing radiofrequency (RF) ablation, 12 (4.1%) (4 females, mean age 36 ± 20 years) developed sustained AF which did not stop spontaneously within 10 min, and antazoline in 100 mg repeated boluses was administered. In all 12 patients the drug restored sinus rhythm after a mean of 425 ± 365 s (range 43-1245 s) using a mean cumulative dose of 176 ± 114 mg (range 25-400 mg). The drug slightly prolonged R-R intervals during AF (from 383 ± 106 to 410 ± 70 ms) and reduced the percentage of fully pre-excited QRS complexes (from 35% to 26%). Intracardiac recordings showed gradual increase in A-A intervals, as well as regularization and decreasing fractionation of atrial activity following drug injection (mean A-A interval of 162 ± 30 ms at baseline vs. 226 ± 26 ms shortly before sinus rhythm restoration, p < 0.001). AP was not completely blocked in any patient which enabled continuation of ablation.
  
  
  CONCLUSIONS
  Antazoline safely and rapidly converts AF into sinus rhythm during ablation of AP. The drug does not block AP completely, enabling continuation of ablation. The drug converting AF into more organized atrial activity (atrial flutter/tachycardia) before sinus rhythm resumption.
authors.affiliation: Department of Cardiology, Grochowski Hospital, Postgraduate Medical School, Warsaw, Poland. rpiotrow@op.pl.
authors.forename: Roman
authors.initials: R
authors.lastname: Piotrowski
authors.forename: Tomasz
authors.initials: T
authors.lastname: Kryński
authors.forename: Jakub
authors.initials: J
authors.lastname: Baran
authors.forename: Piotr
authors.initials: P
authors.lastname: Futyma
authors.forename: Sebastian
authors.initials: S
authors.lastname: Stec
authors.forename: Piotr
authors.initials: P
authors.lastname: Kułakowski
mesh_terms: D058606:Accessory Atrioventricular Bundle / Q000601:surgery*; D000328:Adult; D000865:Antazoline / Q000008:administration & dosage*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D017115:Catheter Ablation; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000503:physiopathology*; D006339:Heart Rate / Q000187:drug effects; D006634:Histamine H1 Antagonists / Q000008:administration & dosage; D006801:Humans; D007275:Injections, Intravenous; D007431:Intraoperative Complications / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D014927:Wolff-Parkinson-White Syndrome / Q000503:physiopathology / Q000601:surgery*
chemical_list: D006634:Histamine H1 Antagonists; D000865:Antazoline