Abstract
OBJECTIVES: Extracorporeal circulation is associated with ischaemia-reperfusion-induced oxidative stress and atrial fibrillation (AF). Ageing is the major risk factor for this arrhythmia. Reinforcing the antioxidant defence system would be expected to protect the myocardium against ischaemia-reperfusion damage. We studied the effect of antioxidant reinforcement and ageing on the occurrence of postoperative AF. METHODS: A randomized, double-blind, placebo-controlled trial was performed in patients scheduled for cardiac surgery with extracorporeal circulation. Supplementation with omega-3 polyunsaturated fatty acid (PUFA) and vitamins C and E, or placebo was administered to 152 patients divided by age: young patients (30-59 years) and old patients (60-80 years). For the detection of AF, we used 12-lead and Holter EKGs. Antioxidant enzyme activity was determined in atrial tissue. Oxidative stress was assessed through plasma malondialdehyde levels. RESULTS: Supplemented patients over 60 years old showed higher glutathione peroxidase activity than control patients in the same age range. There was no difference between the supplemented and placebo groups in patients under 60 years old. The decrease in the incidence of postoperative AF in supplemented patients was more marked in the older patients than in the younger ones. CONCLUSIONS: Since the antioxidant supplementation with n-3 PUFAs and vitamins C and E resulted in a more marked reduction of postoperative AF in older patients, it could be suggested that the efficacy of this therapy improves with ageing.