title: High-degree atrioventricular block during anti-arrhythmic drug treatment: use of a pacemaker with a bradycardia-detection algorithm to study the time course after drug withdrawal.
abstract: OBJECTIVE
  This study examines the recurrence of high-degree atrioventricular block (AVB) during a follow-up period of 2 years in patients with restored AV node function after antiarrhythmic drug withdrawal at implantation of a pacemaker.
  
  
  METHODS
  Nine men and eight women (77 +/- 7 years) taking antiarrhythmic drugs (beta-receptor blockers in 15) and presenting with high-degree AVB were followed for 2 years after being taken off drugs upon receiving a permanent pacemaker with special bradycardia detection software.
  
  
  RESULTS
  At inclusion, surface ECG identified two subsets of patients: a QRS duration < 120 ms (n = 5) and those with a QRS duration > or =120 ms (n = 12). During the 2-year follow-up, progression to high-degree AVB occurred in these groups: 1/5 (20%) and 9/12 (75%) P < 0.05. Six patients had to be restarted on drugs, mostly beta-receptor blockers, due to atrial tachyarrhythmias: 3/5 and 3/12. In total, 16 patients (94%) either developed high-degree AVB needing pacing or atrial tachyarrhythmias requiring drug treatment.
  
  
  CONCLUSIONS
  Patients on beta-receptor blocking drugs and QRS width > or =120 ms developing high-degree AVB should be recommended a pacemaker without further investigation or observation.
authors.affiliation: Department of Cardiology, Karolinska University Hospital, Huddinge 14186 Stockholm, Sweden. goran.kenneback@karolinska.se
authors.forename: Göran
authors.initials: G
authors.lastname: Kennebäck
authors.forename: Fariborz
authors.initials: F
authors.lastname: Tabrizi
authors.forename: Peter
authors.initials: P
authors.lastname: Lindell
authors.forename: Rolf
authors.initials: R
authors.lastname: Nordlander
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage* / Q000009:adverse effects; D001919:Bradycardia / Q000209:etiology* / Q000628:therapy*; D005260:Female; D005500:Follow-Up Studies; D006327:Heart Block / Q000209:etiology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012008:Recurrence; D028761:Withholding Treatment
chemical_list: D000889:Anti-Arrhythmia Agents