FMO5 and atrial fibrillation: Neutrophil apoptosis is complex and can be influenced via the activation of NADPHoxidase as a major source of reactive oxygen species (ROS) production [30,31].NADPH oxidases, expressed as NOX isoforms, are present in neutrophils and vascularcells, including endothelial cells and pericytes, which are unchanged in persistentAF but are increased in permanent AF.