Aim To evaluate functional changes in the heart in the long-term following COVID-19 in patients with chronic heart failure (CHF).Material and methods Case reports of 54 patients aged 69.1±9.7 years who had COVID-19 from January 2021 through January 2022 and had been previously diagnosed with NYHA functional class II-III CHF were studied. Two comparison groups were isolated: HF with LV EF >50 % (n=39) and <50 % (n=15). Echocardiography was used to evaluate changes in LV EF and pulmonary artery systolic pressure (PASP) 5-6 months following COVID-19.Results In all CHF patients after COVID-19 at 5.8 months on average, LV EF decreased (median difference, 2.5 %; 95 % confidence interval (CI): 6.99×10–5– 4.99) and PASP increased (median difference, 8 mm Hg; 95 % CI: 4.5–12.9). In the HF group with LV EF <50 %, the decrease in EF was greater than in the group with LV EF >50 % (6.9 and 0.7 %, respectively; p=0.037); furthermore, the CHF phenotype did not influence the change in PASP (p=0.4). The one-factor regression analysis showed that the dynamics of LV EF decrease was significantly influenced by the baseline decrease in LV EF, whereas the change in PASP was influenced by the dynamics of LV EF decrease, presence of dyslipidemia, and statin treatment. Furthermore, the multifactorial analysis showed that prognostically significant factors for long-term changes in LV EF following COVID-19 were male gender (odds ratio (OR), 5.92; 95 % CI: 1.31–26.75; p=0.014), LV EF at baseline <50 % (OR, 0.88; 95 % CI: 0.8–0.96; p<0.001); changes in PASP depended on the presence of dyslipidemia (OR, 0.08; 95 % CI: 0.01–0.84; p=0.018).Conclusion This study showed that COVID-19 in the long term can influence the course of CHF; in this process, HF patients with EF <50 % have progression of systolic dysfunction and PASP, whereas patients with EF >50 % have an isolated increase in PASP.