Atrial fibrillation (also called AFib or AF) is a quivering or irregular heartbeat (arrhythmia) that can lead to blood clots, stroke, heart failure and other heart-related complications. At least 2.7 million Americans are living with AFib. Individuals with early onset atrial fibrillation (AF) are included in this study of cases from the BioVU sample repository. BioVU is Vanderbilt's biobank of DNA extracted from leftover and otherwise discarded clinical blood specimens. BioVU operates as a consented biorepository; all individuals must sign the BioVU consent form in order to donate future specimens. BioVU subjects are de-identified and linked to the Synthetic Derivative enabling researchers to access genetic data/DNA material as well as dense, longitudinal electronic medical record (EMR)... (for more see dbGaP study page.)