Cardiac involvement is a major cause of morbidity and mortality in hypereosinophilic syndrome (HES). It is classified into 3 stages by the degree of eosinophils-mediated heart injury; acute necrotic stage, thrombotic stage, and fibrotic stage. Nonetheless, definitive evidence that each patient passes sequentially through these stages is lacking. We present a case of 48-year-old male patient with dyspnea and peripheral edema who underwent valve replacement surgery due to severe mitral regurgitation. After the valve replacement, HES with cardiac involvement in the thrombotic stage was diagnosed. In the follow-up study, the patient progressed into fibrotic stage of HES.
Keywords: Fibrotic stage; Hypereosinophilic syndrome; Mitral regurgitation; Thrombotic stage.