Abstract
Background: The clinical course of cardiac sarcoidosis is typically subacute, and fulminant cases requiring mechanical circulatory support are rare. Here, we report the case of a patient with pathologically diagnosed cardiac sarcoidosis who presented with fulminant myocarditis and whose cardiac function was improved by aggressive immunosuppressive therapy based on the treatment of giant cell myocarditis. Case Presentation: A 55-year-old woman presented with progressive dyspnoea and nausea that persisted for 1 month and was eventually diagnosed with acute heart failure. Echocardiography showed a reduced left ventricular ejection fraction with thinning of the basal septal wall. During hospitalisation, she experienced ventricular tachycardia and fibrillation attacks, and bradycardia due to a complete atrioventricular block and sinus dysfunction was observed after starting amiodarone. Subsequently, she underwent intra-aortic balloon pump insertion in addition to inotropic agent administration; however, venoarterial extracorporeal membrane oxygenation and Impella 5.0 were needed because biventricular dysfunction progressed. We diagnosed our patient with cardiac sarcoidosis based on the pathological findings revealing inflammatory cell infiltration, including giant cells with extensive fibrosis and granulomas. However, the possibility of giant cell myocarditis could not be ruled out because of the fulminant clinical course; therefore, aggressive immunosuppressive therapy with corticosteroids and cyclosporine was started. Her cardiac function improved, and all mechanical circulatory support and inotropic agents were discontinued. Conclusion: Cardiac sarcoidosis is difficult to differentiate from giant cell myocarditis because they have many similarities in terms of myocardial histopathology and clinical manifestations. While whether the two diagnoses are parts of a single-disease continuum remains debatable, aggressive combination immunosuppressive therapy may contribute to favourable outcomes.