Introduction. The data of epidemiological studies indicate maintaining high prevalence of heart failure (HF) and an unfavorable prognosis for such patients, which creates the need to change the treatment approach. A feature of the case presented is the young age of the patient and a significant effect that was achieved with quadruple therapy for HF with reduced ejection fraction (EF) after myocarditis.Short description. A three-year follow-up of a patient with HFrEF was carried out. In 2019, at the age of 21, the patient had acute myocarditis, diagnosed according to magnetic resonance imaging. The outcome was postmyocarditis cardiosclerosis, complicated by HFrEF. She had two episodes of HF decompensation, followed by hospitalizations in a cardiology hospital. During the treatment, a quadruple therapy was initiated (angiotensin receptor-neprilysin inhibitor, beta-blocker, mineralocorticoid receptor antagonist, sodium-glucose cotransporter 2 inhibitor), against which a significant improve was noted in the form of decrease in congestion symptoms, natriuretic peptide level from 1956 to 501,4 pg/ml, an increase in LVEF from 33% to 39%. The patient is currently on the waiting list for a donor heart transplant.Conclusion. The case report focuses on the complexity of not only the timely diagnosis of myocarditis, but also the treatment of its consequences. The appointment of quadruple therapy for a patient with HF after myocarditis has improved the patient’s clinical condition before heart transplantation. However, this approach needs to be confirmed in a larger number of patients.