Successful early steroid and anticoagulant treatment for Loeffler's endocarditis related to eosinophilic granulomatosis with polyangiitis.

Loeffler's endocarditis is cardiac damage mediated by hypereosinophilia with a poor prognosis. A 45-year-old woman with Loeffler's endocarditis caused by eosinophilic granulomatosis with polyangiitis had hypereosinophilia (blood eosinophil count 32.4 × 109/L) and left ventricular systolic and diastolic dysfunction (left ventricular ejection fraction 45%, e' 5.1 cm/s). Echocardiography showed a left ventricular apical thrombus (32 × 30 mm). The cardiac magnetic resonance imaging scan showed a subacute thrombus (an iso-intensity area on T1-weighted images and a high-intensity area on T2-weighted images). We administered prednisolone and anticoagulant immediately. The eosinophil count rapidly decreased. After 8 weeks, the thrombus gradually decreased in size (28 × 17 mm) and cardiac function improved (left ventricular ejection fraction 58%, e' 8 cm/s). On the follow-up cardiac magnetic resonance imaging scan, the thrombus gradually became organized (the high-intensity area on T2-weighted images became iso-intense). The subendocardial late gadolinium enhancement showed fibrosis only in a small part of the anterior left ventricular wall. Early steroids and optimal anticoagulant therapy may improve cardiac function and prognosis. Additionally, cardiac magnetic resonance imaging may be an important modality for diagnosis and follow-up. <Learning objective: In patients with Loeffler's endocarditis, early steroid treatment inhibits progression to the fibrotic stage and improves cardiac function. Anticoagulants decrease the size of the thrombus and also lead to improvement in left ventricular function. Cardiac magnetic resonance imaging can detect the phase of Loeffler's endocarditis by identifying fibrosis and characteristics of the thrombus. Therefore, cardiac magnetic resonance imaging may be an important modality for diagnosis and follow-up.>.