You pose a good question. Previous studies such as that by Dr. Psaty, “Incidence of and Risk Factors for Atrial Fibrillation in Older Adults”, have shown an increased risk for persistent atrial fibrillation in patients with increased left atrial size frequently resulting in worsening of symptoms. It is important to speak with your doctor about anticoagulation, Xa inhibitors, and/or direct thrombin inhibitors to reduce the risk of  blood clots and stroke.