Isoproterenol (ISO, 1–15 nM) increased atrial conduction inhomogeneity index, phospho-Nav1.5 and phospho-CaMKII protein levels and late INa by 108%, 65%, 135% and 87%, respectively, and induced triggered activities and episodes of AF in all hearts studied (p < 0.05). This evidence concerns the gene SCN5A and atrial fibrillation.