Dilated Cardiomyopathy with Eosinophilic Granulomatosis with Polyangiitis in Which Active Myocardial Inflammation Was Only Detected by Endomyocardial Biopsy.

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare type of systemic vasculitis. Cardiac involvement is the main cause of death in patients with this disease. We herein report a case of congestive heart failure in a patient with EGPA. Neither Ga scintigraphy nor cardiac magnetic resonance imaging detected inflammation of the myocardium; however, myocardial biopsy revealed numerous infiltrating inflammatory cells, thereby fulfilling the criteria of inflammatory dilated cardiomyopathy. We improved the left ventricular systolic function by increasing the patient's prednisolone dosage. This case shows that in some cases the detection myocardial inflammation - which allows for appropriate therapy - may only be achieved by myocardial biopsy.