A 68 year-old woman was admitted due to chest pain with dyspnea. Transthoracic echocardiography showed isolated right ventricular dysfunction. Coronary angiogram was normal. Cardiac enzyme was elevated persistently. Under the supposed diagnosis of acute idiopathic myocarditis, she was treated with supportive care but symptom and cardiac enzyme was not improved. After steroid pulse therapy, symptom was improved and cardiac enzyme was normalized. She was discharged with improvement of symptoms.