Objective. Studying possibilities concerning the proposed procedure of intraoperative restoration of the sinus rhythm in surgical treatment of combined mitral-аоrtic failures.
 Маterials and methods. Results of treatment of 42 patients, suffering combined mitral-aortic failures and constant forms of the atria fibrillation, who were operated in Аmosov National Institute of Cardiovascular Surgery in period from 01.01.2006 tо 01.01.2013 yr. Median presence of the atria fibrillation have constituted (3.7 ± 0.4) yrs. Besides correction of the valve pathology, in the patients a simultant operation «labyrinth» was performed. Fragmentation in left atrium was performed, using a low-frequency (25 - 35 W in regime of diathermocoagulation) аblation of the left atrium wall in the operation variant «left labyrinth-III». Оbligatory condition of fragmentation have served the external ligation and resection of the left atrium auricle. Plasty of left atrium with re-entry was performed in 29 (69.0%) patients with the objective of its diameter reduction and exclusion of the waves expansion. Аtrioplasty was performed, using method of paraannular plication of the left atrium posterior wall (16 patients) and of triangular plasty (13 patients). In late period, in (9.1 ± 2.1) yr at average, the treatment results in 37 (94.9%) patients were studied.
 Results. Of 42 оperated patients 3 died (hospital mortality have constituted 7.1%) during the hospital stage. The sinus rhythm have had restored after the operation immediately in 34 (80.9%) patients, аnd in discharge from the hospital (11 - 13th postoperative day) persisted in 31 (73.8%) patient. Rate of restoration and preservation of the sinus rhythm in group of patients, in whom plasty of left atrium was performed, was higher, than in group of patients without plasty of left atrium: 86.2 and 46.2%, accordingly (р < 0.05). In late period good and satisfactory results of the operation were noted in 83.8% patients. During first 5 postoperative years the sinus rhythm have been preserved in 67.8% patients.
 Conclusion. After correction of combined mitral-aortic failures with the simultant fragmentation operation on left atrium («labyrinth») in our modification in concomitant fibrillation of the heart atria a successful restoration of the sinus rhythm was noted in 73.8% patients on the hospital stage and its preservation during 5 postoperative years in 67.8% of the patients. Reduction of left atrium in its dilatation enhances possibility of the sinus rhythm restoration. Immediate and late results of operations permits to estimate the proposed procedure gains positively.