NOS2 and atrial fibrillation: Since many studies have linked oxidative stress to the pathogenesis of AF19, 20, 21, 22, the present study aims to test if rapid pacing would induce iNOS expression by the atrial myocyte, and to elucidate the association between the iNOS promoter microsatellite polymorphisms, the iNOS expression in atrial tissue, and the risk of AF.