Introduction: Infective endocarditis (IE) is a severe septic disease, characterized by location of microbial graft at the region of native or prosthetic intact valve and other cardiac structures, causing structural damage and systemic embolism. The annual incidence of IE ranges from 3 to 10 cases per 100,000 persons /year, growth trend in patients with new clinical variant of the disease. Heart failure (HF) is the most frequent complication of IE, which is commonly developed at the background of the IE of aortic valve, caused by perforation of native or prosthetic valve cusps, fistulas or prosthetic wound disruption. Perianulare myocardial abscess located in the membranous septum and the atrioventricular node, rhythm and conduction disturbances are common complications of this disease. Methods: Patient V., 58 years old, was hospitalized with following complaints: “candles” fever – 39 – 40 °С, chills, night sweats, loss of weight – 15 kg per month, typical inspiratory dyspnea, palpitations, dry cough and peripheral edema. From anamnestic: sudden onset over two weeks after tooth extraction (3 teeth). Objective: severe overall condition, skin pale pink, hot, humid, with petechiae plant region. Decreased vescular murmur auscultation with rales bullous medium. Respiratory rate is 21 per minute. Heart sounds are rhythmic, cardiac contraction frequency (CCF) – 88 bpm. The first noise decreased, presence of the systolic murmur at the apex of the heart and the diastolic murmur at the aorta. BP – 90/70 mm Hg. Results: Laboratory examination: Hb – 90 g/l, erythrocytes – 3,1×1012/l, white cells – 15×109/l, ESR – 57 mm/h, C-reactive protein – 48 mg/l. Blood cultures: Sta phylococcus aureus, Aspergillus clavatus. EcoCG: non coronary rupture of cusp of aortic valve (AoV). Rupture of cordage of mitral valve (MV). AoV, MV and tricuspid valve (TV) massive vegetation with II – III grade insufficiency. EF – 50%. Diagnosis: IE active form, mixed etiology, with severe trivalvular pathologies. Myocardial abscess. HF NYHA III FC. Treatment: 1. Antibacterial: Fortum, Ciprinol, Daptomycin, Gentamicin. 2. Surgical: prosthesis of AoV and VM with mechanical prostheses. The patient was discharged in satisfactory condition with recommendations to continue outpatient treatment. Conclusions: The high mortality of patients with IE is caused by serious complications, especially cardiovascular. Congestive HF is the most common complication conditioned by valvular damage: perforation of native or prosthetic valve cusps, rupture of infected chordate, fistulas or prosthetic wound disruption, myocardial absceses, myocarditis with papillary muscle rupture, which determine an unfavorable elovution and prognosis of IE.