Aim. To establish predictors of left ventricular (LV) dilatation and post-infarction left ventricular aneurysm (LVA) development in patients with ST-segment elevation myocardial infarction (STEMI) and/or with Q wave.Material and methods. This registry study included patients admitted with STEMI and/or with Q wave in the first 24 hours from the disease onset in the period from November 1, 2022 to March 31, 2023. The study included 138 patients. The mean age of the patients was 62±11 years. Treatment and examination were carried out in accordance with the current Russian clinical guidelines (2020) on STEMI. The levels of stimulating growth factor expressed by genome 2 (sST2), proprotein convertase subtilisin-kexin type 9, N-terminal pro-brain natriuretic peptide and high-sensitivity C-reactive protein were determined in patients by enzyme immunoassay on the first day of the disease. The patients were divided into two following groups: group 1 — patients with LV dilatation/LVA, n=25 (18,1%), group 2 — patients without LV geometry disorders, n=113 (81,9%). Univariate and multivariate regression analyzes were performed to determine independent predictors of LV dilation/postinfarction LVA.Results. This study showed that with an increase in sST2 levels by 1 ng/L, the probability of LV dilation/LVA formation increase by 1,53 times. Anterior location of myocardial infarction increases the probability of LV dilation/LVA formation by 63,55 times. An increase in eGFR on day 2 of hospitalization by 1 ml/min/1,73 m2 reduces the probability of LV dilatation/LVA formation by 1,07 times.Conclusion. The study showed that anterior location of myocardial infarction and increased sST2 levels increase the probability of LV dilation/LVA formation.