[Incidence of sinus node dysfunction in patients with long-standing, persistent atrial fibrillation who require simultaneous surgical correction of mitral and tricuspid valve defects and the "Maze IIIB" procedure].

Background: Atrial fibrillation (AF) is the most common disorder of heart rhythm. A series of "Maze" surgery was developed, among which the "Maze III" modification is presently a gold standard for surgical treatment of AF.

Aim: To study the sinoatrial node (SAN) function before and after the "Maze III" surgery.

Materials And Methods: The study included 100 patients (48 males) with persistent and long-standing persistent AF and valve abnormality. Mean age of patients was 59 years and mean AF duration - 4 years. Tachysystolic AF prevailed (62 %); normosystolic AF was observed in 31 % of patients; and bradysystolic - in 7 % of patients. Electric cardioversion was performed for all patients according to the standard method. After successful recovery of the sinus rhythm, the endocardial electrophysiological study (EPS) of the heart was performed. Correction of valve pathology and the "Maze IIIB" surgery were performed on days 1-2 following EPS. The SAN function was evaluated by the time of function recovery (SAN TFR).

Results: Using electric cardioversion, the sinus rhythm was restored in all patients. EPS showed abnormal prolongation of the corrected time for the SAN function recovery (CTSANFR) and sinoatrial conduction time (SACT) in 11 % of patients. In 2 % of patients, the abnormal prolongation of SACT was an isolated conduction disorder. In total, 13 % of patients had SAN dysfunction (SAND). These patients received implantable electric cardioverters after a surgical intervention (correction of valve abnormality and "Maze III"). The sinus rhythm recovered immediately after the surgery. On day 7, steady sinus rhythm was observed in 46 % of patients. During the postperfusion period and on the first day postsurgery, 62 % of patients had replacement atrioventricular nodal rhythm. By the time of discharge from the hospital, the nodal rhythm was observed in 25 % of patients. Starting from day 2, the replacement atrial rhythm developed in 13 % of patients, and by the time of discharge from the hospital, 24 % of patients had a stable atrial rhythm.

Conclusion: Effectiveness of the surgical treatment for persistent and long-standing persistent AF (modified "Maze IIIB" surgery with simultaneous correction of the mitral valve (MV) and the tricuspid valve (TV)) in the early postsurgery period was 95 %. According to data of preoperative endocardial EPS, SAND was observed in 13 % of patients. Following the surgical correction of MV and TV defects and the criomodification of the "Maze IIIB" surgery, signs of SAND requiring implantation of an electric cardioverter were observed in a total of 24 % of patients.