Conclusion
The timing of the initiation of the corticosteroid therapy in patients with CS would affect the echocardiographic response and long-term prognosis following an upgrade to CRT therapy. Earlier initiation of corticosteroids seems to improve the long-term outcomes in patients with CS. Unlike the patients with other NICMs, the echocardiographic response to an upgrade to CRT in patients with CS should be carefully evaluated because of the complex etiologies and impact of immunosuppressive therapy.