Purpose. To assess the disorders of the cardiac conduction system (CCS) that occurred in the early postoperative period after aortic valve (AV) replacement by the Ozaki method.Methods. The study included 256 patients after a successfully performed Ozaki procedure. Patients with a history of open cardiac surgery, with an implanted pacemaker, with permanent atrial fibrillation, with simultaneous Ozaki surgery with correction of another pathology, in case of repeated surgery on AV in the next six months, with lethal outcome, under the age of 18 years, when it is impossible to analyze the CCS dynamics were excluded. The mean age was 57.9±11.1 years, the male sex was 119 people (46.5%), the body mass index was 29.7±5.5 kg/m2 , diabetes was observed in 40 patients (15.6%), anamnesis of CCS disorders in 10 (3.9%), CCS disorders on the baseline electrocardiogram (ECG) in 32 (12.5%). Conduction abnormalities were assessed according to the anamnesis and the results of daily ECG recording.Results. In the early postoperative period, CCS disorders were registered in 35 patients (13.7%), of whom 27 (10.6%) had their first occurrence, and 8 (3.1%) had previously existed. By the time of discharge, persistent CCS disorders (which occurred for the first time and in the case of progression of pre-existing blocks) remained in 11 (4.3%): 8 (3.1%) had bundle branch blocks, 3 (1.2%) had atrioventricular blocks that required implantation of a permanent pacemaker. Patients with pacemaker had initial conduction abnormalities. The most frequent dysfunction of the CСS was the left bundle branch block (LBBB) (45.5%). We analyzed 14 variables as predictors of the onset or progression of persistent CCS disorders. Two independent predictors were identified - the presence of conduction abnormalities on the baseline ECG and the time of cardiopulmonary bypass. In patients with persistent conduction disturbances in the postoperative period, CCS disorders on the baseline ECG were more common - 36.4% compared with patients without CCS disorders after surgery - 11.4% (p=0.035) and there was a longer duration of cardiopulmonary bypass 140.6±41.1 min. and 122.4±26.1 min. respectively (p=0.03).Conclusion. The most frequent disorder of the conduction was the LBBB. None of the first dysfunctions of CCS led to the implantation of the pacemaker. The presence of initial ECG conduction disturbances and the time of cardiopulmonary
