BACKGROUND: Atrial fibrillation occurs after approximately 25% to 45% of 
coronary artery bypass graft (CABG) surgeries. Oxidative stress and related 
electrophysiological remodeling has been proposed as a potential cause of this 
atrial fibrillation. Perioperative supplementation of the antioxidant ascorbic 
acid has been evaluated as a preventive agent. The current investigation was 
conducted to evaluate the efficacy of ascorbic acid in reducing atrial 
fibrillation in CABG patients.
METHODS: A prospective, randomized, placebo-controlled, triple-blind, 
single-institution study was conducted in nonemergency CABG patients. Subjects 
were monitored for episodes of arrhythmia and other complications.
RESULTS: Eighty-nine treatment and 96 control subjects completed the study 
protocol. Demographics, comorbidities, and preoperative drugs were similar 
between groups. Surgical characteristics and postoperative medication use also 
were similar. The incidence of atrial fibrillation was 30.3% in the treatment 
group and 30.2% in the control group (P = .985). No difference was found in 
postoperative complications or mortality.
CONCLUSIONS: Our data indicate that supplementation of ascorbic acid in addition 
to routine postoperative care does not reduce atrial fibrillation after coronary 
artery bypass grafting.