While much has been learned about atrial fibrillation from large animal models, many of these studies are correlative. Genetically-altered mouse models have provided much information about such genetic diseases as the long QT syndrome, but have to date not been utilized much to study atrial fibrillation. The ability to study the importance of a single gene product in pathophysiology make this a potentially powerful tool to understand the causal relationship of several proteins and the substrate for atrial fibrillation. In this manuscript we review the techniques available to study atrial electrophysiology and some of the genetically-altered mouse models that have implications for atrial fibrillation.