Objective. To analyze the results of surgical treatment of patients with mitral valve diseases complicated by atrial fibrillation and high pulmonary hypertension, to identify the main predictors of AF recurrence and to evaluate the effectiveness of preventive administration of amiodarone in these patients. Material and methods. There were 151 patients with mitral valve disease complicated by atrial fibrillation and severe pulmonary hypertension (over 40 mm Hg). Patients have undergone heart valve surgery (control group, n=62) and surgical treatment of mitral valve defect combined with correction of AF (study group, n=89) by using of Maze IV procedure for the period 2015—2017. Radiofrequency destructor was applied under control of transmural lesion. Results. Effectiveness of Maze IV procedure was 66% within 2 years after surgery in patients with mitral valve disease, AF and high pulmonary hypertension. Surgical treatment of AF did not significantly influence pulmonary hypertension in postoperative period. Predictors of recurrent AF were initial left atrial dilatation and duration of arrhythmic anamnesis. These features should be considered in scheduling patients for surgical correction. Conclusion. Maze IV procedure is effective and safe method of surgical correction of AF in patients with mitral valve disease and high pulmonary hypertension. This approach ensures maintaining sinus rhythm in 66% of patients within 2 postoperative years. Isolated surgical treatment of AF has no significant effect on pulmonary hypertension in patients with mitral valve disease complicated by AF and high pulmonary hypertension. Severe pulmonary hypertension significantly worsens the results of surgical treatment of AF in patients with mitral valve diseases (p=0.041) and persists after isolated mitral valve surgery that requires additional specific treatment of this pathology. Predictors of recurrent atrial fibrillation after Maze IV procedure are initial left atrial enlargement over 5.5 cm (p<0.001) and arrhythmic anamnesis over 2 years (p<0.001).