• N-acetylcystein;
  • postoperative atrial fibrillation;
  • coronary artery bypass;
  • open heart surgery


Postoperative atrial fibrillation (POAF) following cardiac surgery is a frequent complication with multifactorial etiologies. Recently inflammation due to enhanced oxidative stress has been implicated in its pathogenesis. N-acetylcysteine (NAC) is a promising and novel antioxidant agent. The purpose of this study was to evaluate the efficacy of high-dose oral-NAC for prevention of POAF.


Two hundred and forty patients were randomized in this prospective, double blind placebo-controlled trial to either 1,200-mg oral-NAC two times a day (n = 120) or placebo (n = 120) starting 48 hours before and up to 72 hours after open heart surgery.


The mean age was about 60 years, and 75% were male. Patients in the NAC group were older, with higher percentage of acute coronary syndrome, hypercholesterolemia, and left internal mammary artery use. Coronary involvement and hypertension were more prevalent in the placebo group. All other baseline patient characteristics were similar between groups. Overall POAF developed in 13.8% of the patients. There was no difference in the incidence of POAF between the NAC vs placebo groups (11.7% vs 15.8%, respectively; P = 0.34). Postoperative hospital stay, morbidity, and mortality were similar in both groups.


Prophylactic high-dose oral-NAC begun 2 days before open heart surgery and continued for 5 days, and had no significant effect on the incidence of POAF, in-hospital stay, and postoperative morbidity or mortality.