Introduction
Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by noncaseating granulomas in involved organs.1 Cardiac involvement in sarcoidosis occurs in 20-27% of cases in the United States and may be as high as 58% in Japan.2 Cardiac sarcoidosis (CS) manifestations include various types of tachy- and brady-arrhythmias, left ventricular (LV) systolic dysfunction, and sudden death, and it is increasingly recognized for its poor prognosis.3-6Corticosteroids are widely used as the first-line immunosuppressants for patients with CS, especially in patients who have active inflammation in the myocardium. However, patients with CS are sometimes not diagnosed in the early stage of the disease (e.g. during pacemaker or implantable cardioverter defibrillator [ICD] implantations for atrioventricular block or ventricular arrhythmias), and later are diagnosed with CS due to a cardiac function decline.7 For those patients, it is not well known which therapeutic strategy should come first, corticosteroids therapy or an upgrade to CRT therapy from a pacemaker or ICD. Generally, the clinical response and long-term survival have been less favorable in patients undergoing CRT upgrades than de novo implantations.8However, the pathophysiology of CS greatly differs from that of other cardiomyopathies, and corticosteroid therapy would have a potential to affect the clinical response and long-term prognosis. Thus, in the present study, we investigated the echocardiographic response and long-term prognosis in patients with non-ischemic cardiomyopathy (NICM) who underwent CRT upgrade therapy and analyzed the impact of the timing of the initiation the corticosteroid therapy on the clinical outcomes in patients with CS.