title: Risk factors analysis on failure of maze procedure: mid-term results.
abstract: OBJECTIVE
  Since the late 1980s, surgical ablation of atrial fibrillation (AF) has been one of the most effective means of curing this arrhythmia. However, about 20% of patients who underwent maze procedures have shown recurrence of AF during the follow-up periods. The aim of this study is to evaluate our result of maze procedures in last decade and to analyze the risk factors of maze failure.
  
  
  METHODS
  Between July 1997 and July 2007, 560 consecutive patients underwent maze procedures for AF by a single surgeon. Demographics showed that average age of the patients is 51.3 years, with a slight female predominance (M:F = 248:312). Most of the maze procedures had been performed in conjunction with mitral valve (n = 494, 88.6%), while only six cases (1.1%) were performed with isolated maze procedure. The maze failure was defined as showing any rhythm besides normal sinus rhythm at the last follow-up. Univariate and multivariate analysis for the risk factors of maze failure were identified. The survival impact of maze failure was also evaluated.
  
  
  RESULTS
  The in-hospital mortality (1.6%) was acceptable. During the 29.7 months of median follow-up period, the late mortality rate was 3.8% and permanent pacemaker insertion was necessary in 2.3% (n = 13) of the patients. The success rate of maze was 84.1% (471/560) and effective left atrial contraction was identified in 97.2% (458/471) of these patients. In multivariate analysis, the size of left atrium larger than 60 mm, cardiothoracic ratio over 60%, fine AF wave in preoperative ECG, no early normal sinus restoration and simplified surgical ablation were found as an independent predictor of maze failure. Furthermore, the patients with successful maze showed better long-term survival rates.
  
  
  CONCLUSIONS
  The results of our maze procedure during the last decade showed an acceptable success rate and the patients who were restored to sinus rhythm after maze procedures showed better long-term survival rates. For the patients who have independent biological risk factors, more thorough ablation lesion set is recommended for better long-term results.
authors.affiliation: Department of Cardiovascular Surgery, Pusan National University Yangsan Hospital, Yangsan, South Korea.
authors.forename: Hyung Gon
authors.initials: HG
authors.lastname: Je
authors.forename: Jae Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Jung
authors.forename: Suk Jung
authors.initials: SJ
authors.lastname: Choo
authors.forename: Hyun
authors.initials: H
authors.lastname: Song
authors.forename: Sung Cheol
authors.initials: SC
authors.lastname: Yun
authors.forename: Cheol Hyun
authors.initials: CH
authors.lastname: Chung
mesh_terms: D000328:Adult; D000368:Aged; D001281:Atrial Fibrillation / Q000150:complications / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects / Q000379:methods*; D004812:Epidemiologic Methods; D005260:Female; D006349:Heart Valve Diseases / Q000150:complications / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery; D012008:Recurrence; D017211:Treatment Failure