Aim. To assess the potential of prevention cardiogenic embolism by resection of left atrium appendage (LAA) during open heart surgery in patients with atrial fibrillation (AFib). Materials and methods. Study design - cohort prospective. Study group consisted of 19 patients with AFib whom during open heart surgery for coronary and/or valvular disease additional radical resection of LAA was made. After removal of the appendage two-layer linear suture to left atrium was performed without leaving a stump. Control group consisted of 20 patients with AFib, in whom during open heart surgery LAA remained intact. Long-term results were studied using CROQ telephone questionnaire. Results. There was no hospital mortality in both groups. Long-term results in control group were followed up to 6 years, in study group up to 2 years. Radical resection of LAA in patients with AFib reduced the risk of thromboembolic events in long-term period. In control group there were 4 strokes (2 of them were fatal), but no strokes in study group (p < 0,05). Conclusion. Radical resection of LAA in patients with AFib during open heart surgery for coronary and/or valvular disease prevents cardiogenic arterial embolism. (For citation: Sotnikov AV, Melnikov MV, Marinin VA, et al. Prevention of embolism in patients with atrial fibrillation after resection of left atrium appendage during open heart surgery (pilot study). Herald of North-Western State Medical University named after I.I. Mechnikov. 2018;10(2):52-57. doi: 10.17816/mechnikov201810252-57).