Managing Stroke Risk in Moyamoya Disease With Paroxysmal Atrial Fibrillation: A Case Report.

Moyamoya disease is a progressive cerebrovascular disorder characterized by the narrowing and occlusion of arteries at the base of the brain, leading to the development of collateral vessels, which increases the risk of both ischemic and hemorrhagic strokes. The presence of atrial fibrillation (AF), particularly in a patient with Moyamoya disease, complicates the management strategy due to the dual risks of thromboembolism and hemorrhage. We present a case of a 40-year-old female with a history of unilateral right-brain Moyamoya disease, treated surgically, and with two prior strokes, left carotid stenosis, and hypertension. She was undergoing evaluation for arrhythmia with an implantable loop recorder (ILR) in place and presented to the ED with palpitations. Her ILR was interrogated, revealing two episodes of paroxysmal AF. Heart rate control was achieved with beta-blockers. Due to an elevated CHA₂DS₂-VASc score of 5, anticoagulation was recommended. However, there was concern about the increased risk of spontaneous cerebral hemorrhage in the setting of Moyamoya disease. After consulting with a neurologist and weighing the risks versus benefits, the patient was started on apixaban. Regarding the management of her AF, the patient expressed interest in pursuing catheter ablation; however, the procedure had not been performed at the time of this report. This case highlights the complexity of managing patients with both Moyamoya disease and paroxysmal AF. Treatment should be individualized, considering the benefits and risks of anticoagulation versus antiplatelet therapy, with an emphasis on stroke prevention while minimizing the risk of bleeding.