Aim. To identify predictors of heart failure in patients with dilated cardiomyopathy (DCM) and ischemic myocardial dilatation (IMD).Material and methods. In total, we examined 221 patients with cardiomyopathies: DCM and IMD. The mean age of the patients was 55,30±9,69 years (minimum — 20 years, maximum — 77 years). From the total number of patients, a group of patients with DCM (idiopathic origin) (group 1) was identified in the amount of 111 people, of which 99 were men (89,2%) and 12 women (10,8%). The mean age of patients with DCM was 51,73±9,74 years, for men — 51,00±8,96 years, for women — 57,75±3,71 years. The median age in DCM patients was 53,00 [48,00; 58,00], for men — 53,00 [46,00; 57,00], in women — 59,50 [49,00; 68,75]. Patients with IMD (ischemic origin) consisted of 110 people (group 2), of which 100 were men (91,5%) and 10 women (8,5%). The mean age of patients with IMD was 58,68±8,38 years, for men — 58,29±8,46 years, for women — 62,90±6,29 years. The median age in patients with IMD was 58,00 [53,50; 63,50], in men — 58,00 [52,00; 63,00], in women — 61,50 [59,25; 66,00]. Biological material (venous blood) was taken from all patients for molecular genetic analysis. To isolate the DNA structure, the phenol-chloroform extraction was used. Using the polymerase chain reaction, genotyping of gene polymorphisms was carried out, followed by analysis of restriction fragment length polymorphisms.Results. To assess the left ventricular systolic function, the ejection fraction was assessed. Heart failure and its severity are most often associated with a decrease in left ventricular (LV) systolic function. In our study, in the group of patients with DCM, the mean LV ejection fraction (EF) was 25,105±6,76, while in IMD group — 20,255±4,49 (p=0,0001). This confirms that these two groups have severe heart failure associated with impaired LV systolic function — a decrease in EF <30%. In patients with NYHA class III heart failure with IMD, there was a significant predominance of the heterozygous genotype (6a/5a) of the MMP3 gene polymorphism compared to the control group (66,7% vs 12,5%, p=0,023).Conclusion. The heterozygous genotype of the MMP3 gene polymorphism can be considered as a predictor of the development of HF in patients with IMD for the purpose of early diagnosis and prevention of heart failure. In the group of patients with DCM, no differences were found during a comparative analysis with gene polymorphism.