Effectiveness of methotrexate as a second-line treatment for cardiac sarcoidosis assessed via (18)F-FDG PET: a case report

BACKGROUND: Although methotrexate has been widely used as a second-line therapy for cardiac sarcoidosis (CS), it is not clear if it has a direct anti-inflammatory effect. CASE SUMMARY: A 65-year-old man presented to our hospital with symptomatic ventricular tachycardia (VT). After cardioversion, electrocardiography showed a first-degree atrioventricular block with a right bundle branch block, and transthoracic echocardiography revealed left ventricular dilatation. After extensive investigations, including fluorine-18 fluorodeoxyglucose positron emission tomography ((18)F-FDG PET), the patient was diagnosed with CS according to the Japanese Circulation Society guidelines. After the implantation of a transvenous implantable cardioverter defibrillator, corticosteroid therapy was introduced at a starting dose of 30 mg/day. After corticosteroid therapy was tapered to a maintenance dose of 10 mg/day, he had an uneventful clinical course without symptoms for the 1st year after hospital discharge. However, symptomatic VT recurred and (18)F-FDG PET showed abnormal patterns of cardiac FDG uptake. Although he was treated with corticosteroid therapy once more, which was gradually up-titrated to a dose of 20 mg/day over a 1-month period, myocardial uptake of (18)F-FDG PET remained unchanged. As the patient was considered steroid refractory, second-line treatment with 6 mg/week of methotrexate was introduced, whereas maintaining the dose of corticosteroid therapy at 20 mg/day. After 1 month, (18)F-FDG PET showed remarkable reduction in FDG uptake, and the patient had a good clinical course without further episodes of arrhythmia or other symptoms during an 8-month follow-up. DISCUSSION: Methotrexate may have a direct anti-inflammatory effect in patients with CS refractory to regular corticosteroid therapy.