Our primary hypothesis is that a risk score comprised of approximately 10 single nucleotide polymorphisms (SNPs) that are associated with atrial fibrillation at the Genome Wide Association Study (GWAS) level is associated with the development of atrial fibrillation among previously undiagnosed patients at high risk for atrial fibrillation. A current example of these SNPs is shown in Table 1. As a secondary hypothesis, we will test the association between atrial fibrillation diagnosed in this study with a subset of SNPs reported to be associated with atrial fibrillation and with fine-mapping SNPs. We will also test the association between atrial fibrillation of less than and greater than 30 seconds and a panel of approximately 10 SNPs.