Management of Loeffler's Endocarditis With Bivalvular Involvement and a FIP1L1/PDGFRA-Negative Mutation.

Hypereosinophilic syndromes (HESs) are a group of disorders characterized by end-organ damage caused by eosinophilic infiltration. We present a patient with idiopathic HES with severe tricuspid and mitral regurgitation secondary to Loeffler's endocarditis. In addition to prednisone, imatinib therapy initially helped control the eosinophil count. However, successful long-term remission was achieved with hydroxyurea therapy.