• Occurence of post-operative atrial fibrillation requiring treatment after open heart surgery [ Time Frame: 5 postoperative days ] [ Designated as safety issue: No ]
  

• Mortality [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Hospital Length of Stay [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• ICU Length of Stay [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Stroke [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Low Output Heart Failure [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Postoperative Vasoplegia [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Respiratory Failure requiring reintubation [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Bradycardia necessitating permanent pacemaker placement [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Acute Kidney Injury [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Readmission to ICU for treatment of atrial fibrillation [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  
• Readmission to hospital for treatment of atrial fibrillation [ Time Frame: 30 days ] [ Designated as safety issue: No ]
  

Atrial fibrillation is a common complication of cardiac surgery which is associated with increased morbidity, length of stay and cost. Efforts to mitigate this problem with beta blockers and amiodarone have been met with limited success. Observational data suggests that prophylactic amiodarone has been helpful in decreasing the incidence of AF as well as increasing its ease of management. The opportunity to use ascorbic acid for AF prophylaxis is attractive because of its low side effect profile, wide acceptance and low cost.

We have designed a prospective, randomized, controlled trial using a 2 X 2 factorial design to determine whether prophylactic ascorbic acid alone, ascorbic acid with amiodarone, or amiodarone alone, when given along with beta blockers will decrease the incidence of postoperative AF in adult cardiac surgery in all comers as compared with beta blockers alone.

Patients will be randomized into four groups, A, B, C, and D. All groups will receive beta blockers, Group A will receive beta blockers, ascorbic acid, and amiodarone, Group B will receive ascorbic acid and Beta blockers, Group C will receive amiodarone and beta blockers and Group D will receive only beta blockers.

Success of randomization will be assessed by comparing treatment groups with respect to baseline characteristics, using t-tests or their nonparametric equivalent (as appropriate) for continuous variables and chisquare tests or Fisher's exact tests for categorical variables. The primary hypotheses of the effects of ascorbic acid and amiodarone on incidence of atrial fibrillation will be tested using chisquare tests for differences in proportions. No adjustment will be made for multiple comparisons since both hypotheses are pre-specified. We will use exploratory analyses including stratification to assess for the possibility of effect modification between ascorbic acid and amiodarone. If an interaction is suggested by these analyses, we will use logistic regression with a cross-product term as a formal statistical test for interaction.