Recovery from complete atrioventricular block caused by idiopathic giant cell myocarditis after corticosteroid therapy

Giant cell myocarditis (GCM) is a rapidly progressive disease that leads to ventricular tachycardia or high-grade atrioventricular (A-V) block, frequently requiring a pacemaker. A 64-year-old woman developed syncope as a result of idiopathic GCM with A-V block. She required both a temporary and a permanent pacemaker. Two-dimensional echocardiography showed severely reduced wall motion. There was no histologic or clinical evidence to suggest sarcoidosis. Despite treatment with diuretics and an angiotensin converting enzyme inhibitor, exertional dyspnea persisted. She received prednisolone 4 months after the onset of complete A-V block in the late phase of GCM. Prednisolone improved A-V nodal conduction in spite of the fact that there was no influence from LV wall motion, and sinus rhythm has continued for more than 2 years. In this patient, prednisolone was effective in the treatment of GCM.