We present the case of a 72-year-old female with Fabry disease who developed an advanced interatrial conduction block and atrial fibrillation, a condition known as Bayés' syndrome. Fabry disease is an X-linked inherited lysosomal storage disorder that results in the accumulation of globotriaosylceramide in various organs, including the heart. While this condition has been shown to cause cardiac conduction disease, Bayés' syndrome as a result of Fabry disease has not been reported in the literature. This case report suggests that Fabry disease may precipitate atrial cardiomyocyte damage at Bachmann's bundle leading to interatrial block and supraventricular arrhythmia.