Atrial fibrillation (AF) is one of the leading causes of heart failure (HF) and is associated with increased risk of stroke, higher overall mortality, deterioration in quality of life of patients and a significant increase in treatment costs. The study of ventricular rate orthostatic reactions (VR OR) in patients with AF may help to improve the diagnosis and results of treatment. The aim of our work was to study the frequency of occurrence of the different types of VR OR and changes in clinical symptoms of AF under therapy with beta-blockers (BB). The study involved 46 patients (20 men and 26 women) aged (55±15) years with average AF duration (6±5) years. All patients received BB during 6 months. Patients were examined before, after 1 month and 6 months of treatment. Changes of AF clinical symptoms (the AF functional class (FC), the class of control of AF, the degree of arterial hypertension (AH), the FC of stable angina, the FC of HF) and the frequency of occurrence of the different types of VR OR at stages of therapy were evaluated. It was shown that patients with AF had all types of VR OR with a predominance of positive ((41±6) %) over the negative ((34±5) %) and missing ((25±5) %). Therapy with BB led to the decrease of the severity and functional classes of AF, AH, stable angina, HF and the significant increase in the frequency of positive VR OR with reaching the frequency of heart rate OR during sinus rhythm.