Introduction. Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by damage of different organs and systems. It has been proven that cardiovascular events are proportionally more frequent in SLE affected persons in comparison with general population of corresponding age and sex. Echocardiography is most oftenly used due to its wide availability, ease of implementation, non-invasiveness, safety for visualization of anatomical features, assessment of structure and function of the heart and main vessels. Syntropic comorbid lesions are the non-random combination of two or more syndromes or nosological units with common genetic and/or etiological and pathogenetic mechanisms in a person, which may under certain circumstances influence each other's course. The aim of the study. To investigate nature and frequency of comorbid heart lesions in patients with systemic lupus erythematosus, diagnosed by echocardiography, to identify and characterize their syntropic variants. Materials and methods. 125 patients were included in the study after signing the voluntary Consent to participate, in accordance with the requirements of the Helsinki Declaration of Human Rights, the Council of Europe Convention on Human Rights and Biomedicine, in a randomized manner with preliminary stratification based on the presence of SLE, as well as heart lesions detected by echocardiography. The study included 110 women (88.00 %) and 15 men (12.00 %) aged 18 to 74 years (mean age 42.48 ±1.12 years). All patients with SLE were stratified into five groups based on the evaluation of SLE activity (Systemic Lupus Erythematosus Disease Activity Index scale - SLEDAI). All participants were patients of the Rheumatology Department of Lviv Regional Clinical Hospital. The study included two phases, during which the nature and frequency of comorbid heart lesions, detected by echocardiography, followed by elimination and characterization of syntropic lesions were determined. Results. About half of SLE patients with comorbid heart lesions have mitral valve (MV) insufficiency, and about 1/3 of patients have mitral valve stenosis with left ventricle (LV) diastolic dysfunction. With decreasing frequency we recorded thickening of the aortic valve (AV) leaflets, increased thickness of the interventricular septum (IS), pericardial effusion, enlargement of the left atrial (LA) cavity, enlargement of the right ventricle (RV), increased thickness of the posterior wall of LV in diastole, prolapse of MV, pulmonary hypertension, insufficiency of the tricuspid valve (TV), increase in the diameter of the ascending aorta, AV insufficiency, systolic dysfunction of the LV, enlargement of the LV cavity in diastole. Mitral stenosis and aortic stenosis were found in one case only. Having studied comorbid heart lesions in SLE affected patients, we found that some of them depend statistically reliable on the activity of disease. Therefore, we consider heart valve thickening, pulmonary hypertension, pericardial effusion, and heart failure to be syntropic heart lesions in patients with SLE. Other lesions, the frequency of detection of which does not depend on the activity of SLE, was related to its accompanying diseases. Conclusions. In patients with SLE, mitral valve insufficiency, thickening of the mitral valve leaflets, diastolic dysfunction of the left ventricle, thickening of the aortic valve leaflets, increased thickness of the interventricular septum, and pericardial effusion dominate among the comorbid heart lesions diagnosed by echocardiography. Syntropic heart lesions in patients with SLE included thickening of the mitral valve leaflets, pulmonary hypertension, pericardial effusion, and mitral valve insufficiency. Keywords: systemic lupus erythematosus, comorbid lesions of the circulatory system, syntropic lesions, heart valve lesions, diagnosis, echocardiography.