title: Long-term effects of the maze procedure on atrial size and mechanical function.
abstract: BACKGROUND
  The Maze procedure is effective in restoring sinus rhythm, but the extensive procedure may have negative effects on atrial mechanical function. Decreased atrial contractility has been observed early after the Maze procedure. The purpose of this study was to determine the long-term effect of the Maze procedure on atrial size and mechanical function.
  
  
  METHODS
  Fifty-two patients with symptomatic atrial fibrillation, without structural heart or valvular disease, underwent the Cox Maze III procedure. Atrial size and mechanical function were assessed by echocardiographic examination at baseline and postoperatively at a mean +/- SD of 6 +/- 1 and 56 +/- 12 months.
  
  
  RESULTS
  The left atrial area was decreased 6 months after the procedure compared with baseline (mean, 15.4 +/- 3.3 vs 17.6 +/- 3.2 cm2, p < 0.01). By 56 months, however, the left atrial area had increased compared with the 6-month follow-up (19.5 +/- 3.9 vs 15.4 +/- 3.3 cm2, p < 0.001), resulting in no difference in left atrial size compared with the baseline values. The left atrial contractility, measured as fractional area change, was significantly reduced at 6 and 56 months of follow-up (0.20 +/- 0.09 and 0.19 +/- 0.07 vs baseline 0.36 +/- 0.09), as was the transmitral A-wave velocity (30 +/- 12 and 28 +/- 8 cm/s vs baseline 40 +/- 15). The same pattern was seen for the right atrium.
  
  
  CONCLUSIONS
  This study shows that the Maze procedure results in a sustained decrease in atrial contractility. The initial reduction in atrial size is later reversed. These findings contradict late improvements in atrial mechanical function after Maze surgery and may have important implications for the risk of thromboembolic complications.
authors.affiliation: Department of Cardiology, University Hospital, Uppsala, Sweden. stefan.lonnerholm@akademiska.se
authors.forename: Stefan
authors.initials: S
authors.lastname: Lönnerholm
authors.forename: Per
authors.initials: P
authors.lastname: Blomström
authors.forename: Leif
authors.initials: L
authors.lastname: Nilsson
authors.forename: Carina
authors.initials: C
authors.lastname: Blomström-Lundqvist
mesh_terms: D001281:Atrial Fibrillation / Q000601:surgery*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D009929:Organ Size; D011446:Prospective Studies; D013997:Time Factors; D014463:Ultrasonography