However, data from the more recent and much larger statin therapy in cardiac surgery (STICS) randomized controlled trial showed no significant effect on the incidence of post-operative AF (odds ratio: 1.04, 95% CI = 0.84–1.34) in 1922 patients randomized to rosuvastatin or placebo,16 raising the question of whether NOX2-derived superoxide production is merely a biomarker of increased AF risk or causal factor in the new onset of AF after cardiac surgery. This evidence concerns the gene CYBB and atrial fibrillation.