Rare Cause of Restrictive Cardiomyopathy: A Case Report of Löffler Endocarditis.

Löffler endocarditis, an idiopathic hypereosinophilic syndrome, can present symptoms of heart failure and peripheral eosinophilia. We present the case of a 46-year-old woman with fatigue, shortness of breath, and edema, who was found to have thrombocytopenia, elevated cardiac biomarkers, and hypereosinophilia (2.96 k/uL). Cardiac MRI revealed hypertrophic cardiomyopathy, right ventricular hypertrophy, and a restrictive filling pattern, raising suspicion for Löffler endocarditis. Despite initial corticosteroid and diuretic treatment, she was readmitted with persistent symptoms. This case highlights the diagnostic imaging and treatment challenges with corticosteroid therapy, to control eosinophilic infiltration and prevent irreversible cardiac damage. Löffler endocarditis should be considered in the imaging differential diagnosis of unexplained heart failure.