CYBB and atrial fibrillation: A previous study showed that two membrane subunits of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (p22phox and gp91phox) were significantly activated in the right atrial appendage (RAAs) tissue of AF patients and that these subunits played important roles in atrial reactive oxygen species (ROS) production and AF pathogenesis [28].