Аtrial fibrillation (AF) still occupies a special place in the structure of cardiovascular diseases, both due to its high prevalence, close association with socially significant diseases, and due to the high risks of death, stroke, and other thromboembolic complications. In turn, a patient with AF is always a comorbid patient, and among extracardiac pathology, the prevalence of diseases of the upper gastrointestinal tract, especially gastroesophageal reflux disease (GERD), pay attention. Recently more and more data have appeared that indicate the non-randomness of this combination. Many authors consider GERD as another independent risk factor for AF, while others propose to consider AF as an extra-esophageal manifestation of GERD, of course, in the absence of other cardiac risk factors. This review discusses the main pathophysiological mechanisms that determine the pathogenetic relationship of AF and GERD, known to date.