Do high levels of n-3 polyunsaturated fatty acids in cell membranes increase the risk of postoperative atrial fibrillation?

OBJECTIVES: Postoperative atrial fibrillation (POAF) has been associated with an inflammatory response to the surgical procedure. n-3 long-chain polyunsaturated fatty acids (LC-PUFA) have been proposed for the prevention of POAF. We investigated the relationship between the plasma concentration of inflammatory mediators, levels of n-3 LC-PUFA in red blood cell (RBC) membrane lipids, and the risk of POAF after coronary artery bypass grafting (CABG). METHODS: A total of 125 patients who underwent CABG were studied. Inflammatory mediators in plasma and the content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in RBC membranes were assessed. RESULTS: Sixty-two patients (49.6%) developed POAF. The POAF group had higher RBC levels of total n-3 LC-PUFA and DHA than did patients remaining in sinus rhythm (p < 0.05). Of the inflammatory mediators, only postoperative interleukin-6 levels differed, being higher in the POAF group (p < 0.05). Inflammatory mediators were not independent predictors of POAF by multivariable logistic regression analysis. Higher levels of DHA and total n-3 LC-PUFA in RBC membranes, measured immediately prior to CABG and on postoperative day 3, were linearly associated with an increased risk of POAF (p < 0.05). CONCLUSIONS: Our findings suggest that inflammatory mediators are not associated with the occurrence of POAF. Interestingly, high n-3 LC-PUFA levels in RBC membranes appear to increase the risk of POAF.

Plasma n-3 and n-6 fatty acids and the incidence of atrial fibrillation following coronary artery bypass graft surgery.

BACKGROUND: The anti-inflammatory or anti-arrhythmic effects of n-3 long-chain polyunsaturated fatty acids (LC-PUFA) may decrease the risk of postoperative atrial fibrillation (POAF), but interventional studies have yielded conflicting results. We examined the association between n-3 LC-PUFA and n-6 LC-PUFA in plasma phospholipids (PL) and POAF in patients undergoing coronary artery bypass grafting (CABG). METHODS: A total of 125 patients undergoing CABG were enrolled in the study. The levels of fatty acids in PL were measured preoperatively and on the third postoperative day. The endpoint was defined as POAF lasting ≥5 min. The incidence of POAF was compared between quartiles of the level of each fatty acid in plasma PL by univariate and multivariable analysis. RESULTS: The incidence of POAF was 49·6%. By univariate analysis, the incidence of POAF increased significantly with each higher quartile of pre- and postoperative docosahexaenoic acid (DHA) and diminished significantly with each higher quartile of pre- and postoperative arachidonic acid (AA). For postoperative total n-3 LC-PUFA, there was a significant U-curve relationship where the second quartile had the lowest incidence of POAF or 25·8%. In multivariable analysis, this U-curve relationship between n-3 LC-PUFA levels and POAF risk was not significant, whereas the association between POAF and DHA or AA remained statistically significant. CONCLUSIONS: This study suggests that n-3 LC-PUFA supplements might prevent POAF in CABG patients with low baseline levels of these fatty acids in plasma PL, but may be harmful in those with high levels. AA may play an important role in electrophysiological processes.

Does treatment with n-3 polyunsaturated fatty acids prevent atrial fibrillation after open heart surgery?

AIMS: To examine the effect of n-3 polyunsaturated fatty acid (PUFA) treatment on the incidence of post-operative atrial fibrillation (POAF). METHODS AND RESULTS: A prospective, randomized, double-blinded, placebo-controlled trial was conducted in patients admitted for coronary artery bypass grafting and/or valvular repair surgery. The patients received either n-3 PUFA capsules, containing a daily dose of 1240 mg eicosapentaenoic acid and 1000 mg docosahexaenoic acid, or olive oil capsules for 5-7 days prior to surgery and post-operatively until hospital discharge. The endpoint was POAF, defined as an episode detected by continuous electrocardiographic monitoring, lasting >5 min. A total of 170 patients were enrolled in the study, and 168 patients underwent surgery. Their median age was 67 (range 43-82) years, and 79.2% were males. There was no difference in baseline characteristics between the n-3 PUFA group (n = 83) and the placebo group (n = 85), and the incidence of POAF was 54.2 and 54.1% (P = 0.99), respectively. Factors associated with POAF included advanced age, peak post-operative C-reactive protein level, valvular surgery, lower body mass index, and non-smoking, but n-3 PUFA concentration in plasma lipids was not associated with POAF. CONCLUSION: There is no evidence for a beneficial effect of treatment with n-3 PUFA on the occurrence of POAF in patients undergoing open heart surgery.