Q-fever endocarditis (QFE) is a rare infection caused by the bacterium Coxiella burnetii, which accounts for 5–6% of culture-negative endocarditis and mainly affects artificial or damaged heart valves. The article describes the case of a 45-year-old man with bicuspid mechanical valves and heart failure who suffered cardiogenic shock with acute heart failure; transesophageal echocardiography showed severe mitral valve dysfunction with blood leakage. Blood cultures were negative despite antibiotics, serological tests confirmed the diagnosis. Complications included biventricular heart failure, recurrent infections, and fluid overload, requiring dialysis, doxycycline and hydroxychloroquine, and multidisciplinary care; surgery was not performed due to high risk and the patient died of multiple organ failure. A review of 53 studies with 421 cases showed that patients were predominantly male (77.4%) with a mean age of 53 years, the aortic valve was most commonly affected (57.5%), blood cultures were negative in 96.2% of cases, and IgG phase I ≥1:800 in 83.7%. Treatment included doxycycline with hydroxychloroquine (52.2%) and surgery in 58.4% of cases, mortality reached 10.6%. The case highlights the importance of serologic testing for negative cultures in patients with prosthetic valves.