Abstract Body (Do not enter title and authors here): Introduction: Atrial fibrillation (AF) decreases sports performance in athletes, and ablation is associated with a greater improvement in performance compared to medication. Endurance sports predispose males to AF more than females. However, once AF develops, it is unknown whether its impact in female athletes differs from that of males.

Aims: To investigate the impact of AF and AF treatments in female versus male athletes.

Methods: An internet-based survey, initiated via StopAfib.org, queried the impact of AF and treatment modalities on sports performance, training, and symptoms. Responses were categorized by reported sex. Reported performance (rated in comparison to personal best), frequency of training, and competition engagement were compared before the onset of AF symptoms versus when symptoms were at their worst, between males and females. These outcomes were similarly compared in relation to participants’ AF treatments.

Results: Between 5/13/2019 and 2/29/2020, 219 female and 772 male athletes, 40% of whom were less than 60s years old, answered the survey. Development of AF was associated with declining reported sports performance, competition, and training frequency, with no significant difference between genders. Ablation in both males and females was associated with greater reported improvement in sports performance than the use of medications. Among 141 female athletes and 509 male athletes who have taken medication currently and/or in the past, 52% and 40% reported side effects, respectively. The most prevalent side effects for both males and females were fatigue/low energy and decreased athletic performance.

Conclusion: Once AF develops, the impact on decreasing sports performance is similar in females and males. Both genders similarly reported more improvement with ablation than medications, which were frequently and similarly associated with side effects for females and males.