title: Isolating the entire posterior left atrium improves surgical outcomes after the Cox maze procedure.
abstract: OBJECTIVE
  The importance of each ablation line in the Cox maze procedure for treatment of atrial fibrillation remains poorly defined. This study evaluated differences in surgical outcomes of the procedure performed either with a single connecting lesion between the right and left pulmonary vein isolations versus 2 connecting lesions (the box lesion), which isolated the entire posterior left atrium.
  
  
  METHODS
  Data were collected prospectively on 137 patients who underwent the Cox maze procedure from April 2002 through September 2006. Before May 2004, the pulmonary veins were connected with a single bipolar radiofrequency ablation lesion (n = 56), whereas after this time, a box lesion was routinely performed (n = 81). The mean follow-up was 11.8 +/- 9.6 months.
  
  
  RESULTS
  The incidence of early atrial tachyarrhythmia was significantly higher in the single connecting lesion group compared with that in the box lesion group (71% vs 37%, P < .001). The overall freedom from atrial fibrillation recurrence was significantly higher in the box lesion group at 1 (87% vs 69%, P = .015) and 3 (96% vs 85%, P = .028) months. The use of antiarrhythmic drugs was significantly lower in the box lesion group at 3 (35% vs 58%, P = .018) and 6 (15% vs 44%, P = .002) months.
  
  
  CONCLUSIONS
  Isolating the entire posterior left atrium by creating a box lesion instead of a single connecting lesion between the pulmonary veins showed a significantly lower incidence of early atrial tachyarrhythmias, higher freedom from atrial fibrillation recurrence at 1 and 3 months, and lower use of antiarrhythmic drugs at 3 and 6 months. A complete box lesion should be included in all patients undergoing the Cox maze procedure.
authors: Division of Cardiothoracic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, Saint Louis, MO 63110, USA.
authors: Rochus K
authors: RK
authors: Voeller
authors: Marci S
authors: MS
authors: Bailey
authors: Andreas
authors: A
authors: Zierer
authors: Shelly C
authors: SC
authors: Lall
authors: Shun-ichiro
authors: S
authors: Sakamoto
authors: Kristen
authors: K
authors: Aubuchon
authors: Jennifer S
authors: JS
authors: Lawton
authors: Nader
authors: N
authors: Moazami
authors: Charles B
authors: CB
authors: Huddleston
authors: Nabil A
authors: NA
authors: Munfakh
authors: Marc R
authors: MR
authors: Moon
authors: Richard B
authors: RB
authors: Schuessler
authors: Ralph J
authors: RJ
authors: Damiano
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000601:surgery*; D006348:Cardiac Surgical Procedures / Q000379:methods*; D017115:Catheter Ablation / Q000379:methods*; D005260:Female; D006325:Heart Atria / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000601:surgery