The article is devoted to a clinical case of management of a young woman with an aneurysm and two atrial septal defects after the development of acute myocardial infarction. It conveys aspects of differential diagnosis and long-term management.

Aim. To evaluate patients with acute coronary syndrome (ACS) in combination with atrial fibrillation (AF) according to the total register of ACS in the Krasnodar region of echocardiographic (EchoCG) parameters (left atrial dimension (LAD), left ventricular wall thickness (LVWT), left ventricle end-diastolic diameter (LVEDD), left ventricular ejection fraction (LVEF), pulmonary artery systolic pressure (PASP), as well as coronary substrate assessment according to coronary angiography (CAG) and determination of the relationship between the value of LVEF and the coronary substrate.Material and methods. From the register of the ACS in the Krasnodar region, patients were successively taken to the cardiology departments of Krasnodar regional clinical hospital № 1 for the period from November 20, 2015 to November 20, 2017 with a diagnosis of ACS, accompanied by one of the types of atrial fibrillation. This group of patients was designated as a group of ACS + AF and amounted to 119 patients. The comparison group was selected with the help of a random number generator from patients admitted to the hospital with ACS and intact sinus rhythm (SR) for the period of time from November 20, 2015 to November 20, 2017 (120). We analyzed the ECHO-CG parameters, the coronary substrate — according to the CAG.Results. When comparing the cohort of patients with ACS + AF with the cohort of patients with ACS + SR, we determined a significant (p<0,05) difference of LA size, LVEF and values of PASP. During comparing the presence of hemodynamically significant stenosis in the coronary arteries we noticed that in ACS + AF patients with LVEF <40% in significantly higher percentage of cases (p=0,0007) occurs significant hemodynamic stenosis of coronary arteries, in contrast to the group of patients with ACS + SR with LVEF <40%. In patients with EF >40% and ACS + SR we determined a significantly more frequent (p<0,001) stenosis.Conclusion. The results of the analysis are important for understanding the distinguishing characteristics of patients with ACS that occur on the background of AF, which is important for correct prediction of the course of the disease. The maintenance of the ACS register will provide information on the real clinical course of the disease, as well as improve the effectiveness of treatment in real clinical practice.