Material and methods. A prospective, randomized, single-center study was conducted. It included 166 patients with mitral valve disease divided into three groups depending on types of AF: with paroxysmal AF at 14 (8.4%) patients, with persistent AF at 63 (37, 9%) patients and with long-term persistent AF at 89 (53.6%) patients hospitalized at the Interregional Clinic and Diagnostic Center Kazan from 2011 to 2018. An average age of patients was 57 ± 5 years old, mainly females amounted to 97 (58.4%).Results. Surgical isolation of the pulmonary vein ostia and the left atrium by RFA at mitral valve replacement significantly improves the contractile function of the left atrium, which allows us to judge about the improvement of the transport function of the left heart chambers as a whole.