title: A novel individualized substrate modification approach for the treatment of long-standing persistent atrial fibrillation: preliminary results.
abstract: BACKGROUND
  The most effective approach for long-standing persistent atrial fibrillation (LPAF) ablation remained undetermined. Our goal was to explore the heterogeneous left atrial substrate in patients with LPAF and to evaluate the effectiveness of a novel individualized substrate modification (ISM) approach in LPAF ablation.
  
  
  METHODS
  One hundred and twenty-four patients with LPAF were randomized to ISM group (n=64) or stepwise ablation (SA) group (n=60). After pulmonary vein isolation, ISM was performed in the ISM group and SA was applied in the SA group. The clinical effectiveness after a single and a repeated procedure was compared.
  
  
  RESULTS
  The total procedural time was significantly shorter in ISM than that in SA. In the ISM group, mild left atrial substrate was observed in 17 (27.4%), moderate in 26 (41.9%) and severe in 19 (30.6%) patients after successful cardioversion of the 62 patients. The intention-to-treat analysis showed that sinus rhythm was maintained in 65.5% of patients in the ISM group and in 45.0% of patients in the SA group after a single procedure, P=0.04. Atrial tachycardia (AT) recurred in 5 of 22 in the ISM group and in 20 of 33 in the SA group, P=0.01. After a repeated procedure, 75% of patients in the ISM group and 63.3% of patients in the SA group were free of further recurrence, P=0.16.
  
  
  CONCLUSIONS
  Left atrial substrate varied noticeably in patients with LPAF. The ISM approach was superior to SA approach in terms of procedural time, recurrence rate of AT and clinical effectiveness after a single procedure. However, they yielded comparable outcomes after a repeated procedure.
authors.affiliation: Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, China.
authors.forename: Xin-Hua
authors.initials: XH
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, China.
authors.forename: Jia-Liang
authors.initials: JL
authors.lastname: Mao
authors.affiliation: Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, China. Electronic address: heben1026@hotmail.com.
authors.forename: Ben
authors.initials: B
authors.lastname: He
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D016896:Treatment Outcome
keywords: Complex fractionated atrial electrograms; Individualized substrate modification; Long-standing persistent atrial fibrillation; Stepwise ablation approach