title: Electrophysiological characteristics and catheter ablation in patients with paroxysmal right atrial fibrillation.
abstract: BACKGROUND
  Catheter ablation of the right atrial (RA) substrate has had variable efficacy in curing paroxysmal atrial fibrillation (PAF), suggesting that RA substrate ablation can play an important role in the treatment of atrial fibrillation (AF) in some patients. The aim of this study was to investigate the electrophysiological characteristics and ablation strategy and its results in a specific group of patients with paroxysmal RA-AF.
  
  
  RESULTS
  The study population consisted of 13 patients (8 men; age, 64+/-15 years) with drug-refractory (2+/-1 drugs), frequent episodes of PAF. Provocation maneuvers did not reveal any ectopic beat-initiating AF. However, rapid atrial pacing easily induced AF. Activation mapping during sinus rhythm, atrial pacing, and AF was visualized by using a noncontact mapping system. Noncontact mapping revealed RA reentry (6 patients with single-loop circuits and 7 with double-loop circuits) with conduction through channels between lines of block, crista terminalis gaps, and the cavotricuspid isthmus, which could be identified during sinus rhythm and atrial pacing, resulting in fibrillatory conduction in other parts of the RA. The consistency of wavefront activation was confirmed by frequency analysis from equally distributed mapping sites in the RA. Short lines of ablation lesions were aimed at the conduction channels between the lines of block, crista terminalis gaps, and the cavotricuspid isthmus, resulting in bidirectional block. AF was eliminated in 11 (85%) of 13 patients, and those 11 patients with acute success were free of AF without any antiarrhythmic drugs during the long-term follow-up period (16+/-6 months).
  
  
  CONCLUSIONS
  RA ablation still can cure selected patients with PAF. Linear ablation of the RA substrate guided by the electrophysiological characteristics of RA-AF is an effective approach for treating this specific group of patients with AF.
authors.affiliation: Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Yenn-Jiang
authors.initials: YJ
authors.lastname: Lin
authors.forename: Ching-Tai
authors.initials: CT
authors.lastname: Tai
authors.forename: Tsair
authors.initials: T
authors.lastname: Kao
authors.forename: Han-Wen
authors.initials: HW
authors.lastname: Tso
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Huang
authors.forename: Satoshi
authors.initials: S
authors.lastname: Higa
authors.forename: Yoga
authors.initials: Y
authors.lastname: Yuniadi
authors.forename: Bien-Hsien
authors.initials: BH
authors.lastname: Huang
authors.forename: Tu-Ying
authors.initials: TY
authors.lastname: Liu
authors.forename: Pi-Chang
authors.initials: PC
authors.lastname: Lee
authors.forename: Ming-Hsiung
authors.initials: MH
authors.lastname: Hsieh
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000628:therapy*; D016280:Atrial Function, Right / Q000502:physiology*; D017115:Catheter Ablation; D004562:Electrocardiography; D004594:Electrophysiology / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018487:Ventricular Dysfunction, Left / Q000453:epidemiology / Q000503:physiopathology