Aagaard P, et al. - In this cross-sectional study, atrial fibrillation (AF) prevalence in former National Football League (NFL) athletes vs population-based controls were compared. In addition, other conduction system parameters were characterized. Four hundred sixty former NFL athletes (age 56±12 years, black 47%) were compared with population-based controls of similar age and racial composition from the cardiovascular cohort Dallas Heart Study-2 (n=925, age 54±9 years, black 53%). Findings revealed increased AF prevalence and slowed cardiac conduction in correlation to former NFL participation when compared with a population-based control group. Former NFL athletes who screened positive for AF were generally rate controlled and asymptomatic, however, there was a necessity for anticoagulation in 80% in view of the stroke risk. Former athletes had sinus bradycardia and first-degree atrioventricular block as typically benign findings but also had a higher prevalence of more severe conduction abnormalities requiring cardiac pacing.