title: Do antioxidant vitamins have an anti-arrhythmic effect following cardiac surgery? A meta-analysis of randomised controlled trials.
abstract: BACKGROUND
  Postoperative atrial fibrillation (POAF) affects approximately 30% of patients undergoing elective cardiac surgery. While its pathogenesis is multifactorial, increasing evidence supports a role for oxidative stress in the electrophysiological remodelling associated with AF. Although prophylactic antioxidants appear to be a potentially attractive pharmacotherapy, there is still uncertainty regarding their efficacy. This study aims to provide a quantitative summary of the current evidence surrounding antioxidant vitamins and POAF prevention.
  
  
  METHODS
  A systematic literature review identified five randomised controlled trials incorporating 567 patients (n = 284 antioxidant, n = 283 control). These were meta-analysed using random effects modelling. Heterogeneity, subgroup analysis, quality scoring and risk of bias were assessed. Primary endpoints were the incidence of POAF and all-cause arrhythmia. Secondary endpoints were length of stay in the intensive care unit (ITU) and length of hospital stay.
  
  
  RESULTS
  Vitamins C and E significantly reduced the incidence of POAF (OR 0.43, 95% CI 0.21 to 0.89) and all-cause arrhythmia (OR 0.54, 95% CI 0.29 to 0.99) compared with controls. A significant reduction in both ITU stay (weighted mean difference (WMD) -0.44, 95% CI -0.70 to -0.17) and hospital stay (WMD -1.11, 95% CI -1.70 to -0.52) was also seen in the antioxidant group, without significant heterogeneity.
  
  
  CONCLUSIONS
  The prophylactic use of vitamins C and E may significantly reduce the incidence of POAF and all-cause arrhythmia following cardiac surgery. However, the overall quality of current studies is poor and further research should focus on adequately powered randomised controlled trials that standardise AF reporting, antioxidant protocol and the use of concomitant agents. Cost analysis should be considered to establish the potential economic benefit of antioxidant vitamin prophylaxis in POAF.
authors.affiliation: Department of Surgery and Cancer, Imperial College London, 10th Floor QEQM Building, St Mary's Hospital, London W2 1NY, UK. leanne.harling@imperial.ac.uk
authors.forename: Leanne
authors.initials: L
authors.lastname: Harling
authors.forename: Sonia
authors.initials: S
authors.lastname: Rasoli
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Vecht
authors.forename: Hutan
authors.initials: H
authors.lastname: Ashrafian
authors.forename: Antonios
authors.initials: A
authors.lastname: Kourliouros
authors.forename: Thanos
authors.initials: T
authors.lastname: Athanasiou
mesh_terms: D000975:Antioxidants / Q000627:therapeutic use*; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome; D014815:Vitamins / Q000627:therapeutic use*
chemical_list: D000975:Antioxidants; D014815:Vitamins