A 36-year-old male patient was hospitalized due to persistent chest tightness and dyspnea lasting over 10 days. An echocardiogram revealed significant aortic valve regurgitation， the presence of vegetation on the aortic valve， severe mitral valve regurgitation， and enlargement of both the left atrium and left ventricle. Following a comprehensive multidisciplinary consultation， the focus was directed towards the aortic valve vegetation as the primary concern， with particular attention given to the potential diagnosis of blood culture-negative infective endocarditis （IE） and non-bacterial thrombotic endocarditis， while differentiating it from rheumatic heart disease. Ultimately， the vegetation was excised during a surgical aortic valve replacement procedure， which facilitated histopathological examination， biological culture， and high-throughput metagenomic sequencing of pathogenic microorganisms. The definitive diagnosis was established as aortic valve infective endocarditis （Q fever IE） leading by infection of Coxiella burnetii.