Patients with abnormal origin of coronary arteries from the contralateral sinuses of Valsalva have a highly variable clinical symptoms and mortality prognosis. The main clinical manifestations are associated with myocardial ischemia due to the discharge of the coronary artery at an acute angle from the aorta and contracting in the proximal part. Determining the optimal treatment strategy for this category of patients is extremely difficult due to the small number of cases and the lack of a unified database of tracking such patients. There are no publications on the above topics in Russia, therefore our diagnostic search and the choice of treatment tactics are based on the experience of foreign colleagues. Here we present a special case of an abnormal origin of the right coronary artery from the left sinus of Valsalva in a 22-year-old girl with a clinic of syncopal states and 4B Lown's grading of ventricular premature beats. During the diagnostic search, the exact cause of the above clinical manifestations is determined. The optimal drug therapy was chosen due to the lack of evidence base to improve the prognosis in patients after surgery. During the year of observation according to the data of the Reveal implanted device for the long-term electrocardiogram monitoring, lifethreatening arrhythmias were not detected.