For example, citrate synthase, which plays an important role as the first enzyme in the citric acid cycle by converting oxaloacetate and acetyl CoA to citrate and CoA‐SH17 is down‐regulated in various types of heart failure.12 In addition, mitochondrial dysfunction and citrate synthase down‐regulation have been shown to be exacerbated by atrial fibrillation.11 In our study, not only citrate synthase, but also the entire glycolytic pathway were down‐regulated. The gene discussed is CS; the disease is atrial fibrillation.