title: Association of atrial nicotinamide adenine dinucleotide phosphate oxidase activity with the development of atrial fibrillation after cardiac surgery.
abstract: OBJECTIVE
  Our goal was to evaluate the role of myocardial nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and plasma markers of oxidative stress in the pathogenesis of post-operative atrial fibrillation (AF).
  
  
  BACKGROUND
  Atrial fibrillation is a common complication of cardiac surgery, leading to increased morbidity and prolonged hospitalization. Experimental evidence suggests that oxidative stress may be involved in the pathogenesis of AF; however, the relevance of this putative mechanism in patients undergoing cardiac surgery is unclear.
  
  
  METHODS
  We measured basal and NADPH-stimulated superoxide production in right atrial appendage samples from 170 consecutive patients undergoing conventional coronary artery bypass surgery. Plasma markers of lipid and protein oxidation (thiorbabituric acid-reactive substances, 8-isoprostane, and protein carbonyls) were also measured in blood samples drawn from a central line before surgery and after reperfusion.
  
  
  RESULTS
  Patients who developed AF after surgery (42%) were older and had a significantly increased atrial NADPH oxidase activity than patients who remained in sinus rhythm (SR) (in relative light units/s/mug protein: 4.78 +/- 1.44 vs. 3.53 +/- 1.04 in SR patients, p < 0.0001). Plasma markers of lipid and protein oxidation increased significantly after reperfusion; however, neither pre-operative nor post-operative measurements differed between patients who developed AF and those who remained in SR after surgery. Multivariate analysis identified atrial NADPH oxidase activity as the strongest independent predictor of post-operative AF (odds ratio 2.41; 95% confidence interval 1.71 to 3.40, p < 0.0001).
  
  
  CONCLUSIONS
  Atrial NADPH oxidase activity is independently associated with an increased risk of post-operative AF, suggesting that this oxidase system may be a key mediator of atrial oxidative stress leading to the development of AF after cardiac surgery.
authors.affiliation: University Department of Cardiovascular Medicine, John Radcliffe Hospital, Oxford, United Kingdom.
authors.forename: Young M
authors.initials: YM
authors.lastname: Kim
authors.forename: Hassan
authors.initials: H
authors.lastname: Kattach
authors.forename: Chandi
authors.initials: C
authors.lastname: Ratnatunga
authors.forename: Ravi
authors.initials: R
authors.lastname: Pillai
authors.forename: Keith M
authors.initials: KM
authors.lastname: Channon
authors.forename: Barbara
authors.initials: B
authors.lastname: Casadei
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000209:etiology / Q000503:physiopathology*; D015415:Biomarkers; D001026:Coronary Artery Bypass / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019255:NADPH Oxidases / Q000097:blood / Q000378:metabolism*; D018384:Oxidative Stress; D011183:Postoperative Complications; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D019255:NADPH Oxidases