title: Prospective assessment of the CryoMaze procedure with continuous outpatient telemetry in 136 patients.
abstract: BACKGROUND
  Only 40% of patients with atrial fibrillation (AF) undergoing cardiac surgery are treated with surgical AF correction. We prospectively studied endocardial cryoablation of the Cox-maze III lesion set following prespecified rhythm assessment with outpatient telemetry.
  
  
  METHODS
  Between 2007 and 2011, 136 patients underwent surgical AF correction using an argon-powered cryoablation device. Patients wore continuous electrocardiogram monitoring prior to and at 6, 12, and 24 months after surgery. The average length of monitoring was 6.5±1 days prior to surgery and 11±4 days at each time point after surgery. Patients were assessed for cardiac rhythm, interval cardioversion or ablation procedures, pacemaker placement, and the use of warfarin or antiarrhythmic medications. The primary endpoint of this study was freedom from AF at 1 year.
  
  
  RESULTS
  Mean patient age was 66±12 years, 50% (69 of 138) were male and 41% (55 of 134) had persistent AF. CryoMaze was done in conjunction with mitral valve operation in 95% (131 of 138) and other procedures in 41% (56 of 138). Follow-up was 96% complete at 1 year and 90% at 2 years. Freedom from AF was 76% at 1 year. Perioperative mortality and stroke rates were both 1.5% (2 of 138). Perioperative pacemaker implantation was required in 7% (9 of 136). In univariate analysis, younger age, female gender, decreased height and weight, smaller preoperative and postoperative left atrial diameter, intermittent AF, and freedom from AF at discharge were associated with freedom from AF at 1 year. Actuarial 2- and 4-year (Kaplan-Meier) survival were 93% and 80%, respectively.
  
  
  CONCLUSIONS
  The CryoMaze procedure is safe and is associated with 76% freedom from AF at 1 year.
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland.
authors.forename: A Claire
authors.initials: AC
authors.lastname: Watkins
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland.
authors.forename: Cindi A
authors.initials: CA
authors.lastname: Young
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland.
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Ghoreishi
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Shorofsky
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland.
authors.forename: Joel
authors.initials: J
authors.lastname: Gabre
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland.
authors.forename: Murtaza Y
authors.initials: MY
authors.lastname: Dawood
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland.
authors.forename: Bartley P
authors.initials: BP
authors.lastname: Griffith
authors.affiliation: Division of Cardiac Surgery, University of Maryland, School of Medicine, Baltimore, Maryland. Electronic address: jgammie@smail.umaryland.edu.
authors.forename: James S
authors.initials: JS
authors.lastname: Gammie
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000601:surgery*; D006348:Cardiac Surgical Procedures / Q000379:methods; D003452:Cryosurgery; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D013686:Telemetry