Aim. In this study, we investigated the impact of tirofiban on ventricular performance in patients who were diagnosed with acute coronary syndrome, found to have left main coronary artery stenosis during coronary angiography, and administered tirofiban prior to coronary artery bypass to prevent the recurrence of an acute coronary syndrome during the preoperative period. Material and methods. The patients were divided into two groups. Group 1 included patients who were pre-diagnosed with acute coronary syndrome and administered tirofiban infusion in another hospital and subsequently sent to our center for advanced examination and treatment, where they exhibited left main coronary artery disease during coronary angiography and were submitted to surgery (n=28). Group 2 included patients who arrived at our emergency service with chest pain, were pre-diagnosed with acute coronary syndrome in the cardiology clinic, exhibited left main coronary artery disease during coronary angiography, and were submitted to urgent surgery without receiving tirofiban infusion (n=29). Standard and tissue Doppler echocardiography were applied to each patient in the preoperative and postoperative periods. Results. After bypass surgery, the mean postoperative left ventricular myocardial performance index (0.84±0.30) was significantly lower than the mean preoperative left ventricular myocardial performance index (1.10±0.35) (p=0.001). The left lateral myocardial performance index was lower in group 1 (0.76±0.31) than in group 2 (0.92±0.27) (p=0.050*), but the ejection fraction was higher in group 1 (61.46±7.74) than in group 2 (52.87±11.64) (p=0.003*). Conclusion. Preoperative administration of tirofiban improved postoperative left ventricular performance compared to pretreatment with aspirin alone in patients with left main coronary artery disease undergoing coronary artery bypass surgery. Therefore, we recommend the preoperative administration of tirofiban as an antithrombotic agent to patients who are undergoing coronary artery bypass for left main coronary artery disease. Цель. В этой работе изучено влияние тирофибана на желудочковые показа-тели у больных, которым был поставлен диагноз «острый коронарный син-дром» (ОКС), обнаружен стеноз левой коронарной артерии при коронарной ангиографии и введен тирофибан до операции коронарного шунтирования, чтобы не допустить повторения ОКС в предоперационном периоде. Материал и методы. Больные были разделены на две группы. В группу 1 были включены пациенты, которым был предварительно поставлен диагноз ОКС, введен тирофибан в другой больнице; затем они были направлены в наш центр, им было проведены современное обследование и лечение, под-твержден стеноз левой коронарной артерии при коронарной ангиографии, и пациенты были отправлены на хирургическое лечение (n=28). 2 группа -пациенты, доставленные в наш центр бригадами экстренной помощи, с болью в области груди; им был предварительно поставлен диагноз ОКС в клинике кардиологии, подтвержден стеноз левой коронарной артерии при коронарной ангиографии,...