title: Persistent atrial flutter in patients treated for atrial fibrillation with amiodarone and propafenone: electrophysiologic characteristics, radiofrequency catheter ablation, and risk prediction.
abstract: BACKGROUND
  Antiarrhythmic drugs have been reported to promote the conversion of atrial fibrillation to atrial flutter in patients with paroxysmal atrial fibrillation. However, information about the electrophysiologic mechanism and response to radiofrequency ablation of these drug-induced atrial flutters is limited. Furthermore, the determinants of the development of persistent atrial flutter in patients treated for atrial fibrillation with antiarrhythmic drugs are still unknown.
  
  
  RESULTS
  Among the 136 patients treated for atrial fibrillation with amiodarone (n = 96) or propafenone (n = 40), 15 (11%, mean age 65.5 +/- 12.3 years) were identified to have subsequent development of persistent atrial flutter based on surface ECG characteristics during antiarrhythmic drug treatment. The mean interval between the beginning of drug treatment and the onset of atrial flutter was 5.0 +/- 5.5 months. Intracardiac mapping and entrainment studies revealed that 11 patients had counterclockwise typical atrial flutter, and 4 had clockwise typical atrial flutter. All 15 patients underwent successful ablation with creation of complete bidirectional isthmus conduction block. After a mean follow-up of 12.3 +/- 4.2 months, 14 (93%) of 15 patients who underwent successful ablation and continued taking antiarrhythmic drugs have remained in sinus rhythm. Univariate analysis of clinical variables demonstrated that only atrial enlargement was significantly related to the occurrence of persistent atrial flutter.
  
  
  CONCLUSIONS
  In patients with atrial fibrillation, persistent typical atrial flutter might occur during antiarrhythmic drug treatment, and atrial enlargement was a risk factor for the development of such an arrhythmia. Radiofrequency ablation and continuation of pharmacologic therapy offered a safe and effective means of achieving and maintaining sinus rhythm.
authors.affiliation: Department of Medicine, National Yang-Ming University, School of Medicine, Veterans General Hospital-Taipei, Taiwan, Republic of China. cttai@vghtpe.gov.tw
authors.forename: C T
authors.initials: CT
authors.lastname: Tai
authors.forename: C E
authors.initials: CE
authors.lastname: Chiang
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: Y J
authors.initials: YJ
authors.lastname: Chen
authors.forename: W C
authors.initials: WC
authors.lastname: Yu
authors.forename: A N
authors.initials: AN
authors.lastname: Feng
authors.forename: Y A
authors.initials: YA
authors.lastname: Ding
authors.forename: M S
authors.initials: MS
authors.lastname: Chang
authors.forename: S A
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000638:Amiodarone / Q000009:adverse effects* / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects* / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D001282:Atrial Flutter / Q000139:chemically induced* / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011405:Propafenone / Q000009:adverse effects* / Q000627:therapeutic use
chemical_list: D000889:Anti-Arrhythmia Agents; D011405:Propafenone; D000638:Amiodarone