A Survival Case of Fulminant Right-Side Dominant Eosinophilic Myocarditis.

A 59-year-old Japanese woman was admitted to a nearby hospital with dyspnea and general malaise. Transthoracic echocardiography revealed right ventricular (RV) dilatation with severely reduced systolic function and leftward shift of the intraventricular septum. She was initially diagnosed with acute right heart failure, and fell into cardiogenic shock requiring an intra-aortic balloon pump and inotropic agents. An endomyocardial biopsy (EMB) demonstrated extensive interstitial edema, infiltration of inflammatory cells including numerous eosinophils, and myocytolysis with eosinophil degranulation. She was histologically diagnosed with eosinophilic myocarditis. Steroid pulse therapy was initiated, and her hemodynamic status improved along with dramatic recovery of the RV function. EMB 6 days after the initiation of steroid pulse therapy showed the disappearance of infiltration and degranulation of eosinophils, although lymphocytic infiltration still remained. Positron emission tomography-computed tomography (PET/CT) 23 days after steroid pulse therapy showed an increased F-FDG uptake in the intraventricular septum and left ventricle, suggesting persistent myocardial inflammation. She was then treated with a maintenance dose of prednisolone. She became free of symptoms and follow-up echocardiography showed normal cardiac function 3 months after the initiation of corticosteroid treatment. In addition, EMB and PET/CT showed no inflammation. This is the first case report of fulminant and right-sided dominant eosinophilic myocarditis successfully treated with corticosteroid.