To summarize, according to our results, hydrogen application remarkably ameliorated AngII-mediated AF and atrial fibrosis, which was accompanied by a decrease in NOX4-mediated overproduction of ROS, reduction of the NLRP3 inflammasome, together with downregulation of TGF-β1/smad2/3 pathway. The gene discussed is NOX4; the disease is atrial fibrillation.