Chronic myocarditis is a prolonged inflammatory condition in the myocardium and its histological manifestation is defined by the presence of an inflammatory infiltrate. Chronic myocarditis has not been well known and its treatment of chronic myocarditis has not been established. Primary outcome of this study was to assess the efficacy of immunomodulatory treatment in addition to conventional treatment, and secondary outcomes were to clarity the prognosis of natural history of chronic myocarditis and incidence of chronic myocarditis in patients with dilated cardiomyopathy (DCM). We searched for studies in Medline, Embase, Cochrane Central Register of Controlled Trials, and Igaku Chuo Zasshi published between January 1946 and June 2020. Sixteen studies met the inclusion criteria. A meta-analysis revealed that patients receiving immunomodulatory treatment showed an improvement in left ventricular ejection fraction after immunomodulatory treatment compared to the control group (hazard ratio, 16.65; confidence interval, 4.55–28.74; p = 0.007). Five-year survival rate of the patients with inflammatory DCM (iDCM) and DCM was 52.7–70.3% and 51.9–91.1%, respectively. Moreover, 51.5%–62.7% of patients with DCM met the criteria of iDCM. Our systematic review revealed that patients with chronic myocarditis had poor prognosis and immunomodulatory treatment was significantly effective in addition to conventional treatment.

慢性心肌炎是心肌中的长期炎症状态，其组织学表现由炎症浸润的存在定义。慢性心肌炎尚未广为人知，其对慢性心肌炎的治疗尚未确立。本研究的主要结果是评估除常规治疗外免疫调节治疗的疗效，次要结果是明确扩张型心肌病 (DCM) 患者慢性心肌炎自然病程的预后和慢性心肌炎的发病率。我们检索了 Medline、Embase、Cochrane Central Register of Controlled Trials 和 Igaku Chuo Zasshi 于 1946 年 1 月至 2020 年 6 月期间发表的研究。16 项研究符合纳入标准。p  = 0.007)。炎症性 DCM (iDCM) 和 DCM 患者的五年生存率分别为 52.7-70.3% 和 51.9-91.1%。此外，51.5%~62.7% 的 DCM 患者符合 iDCM 标准。我们的系统评价显示，慢性心肌炎患者预后较差，除常规治疗外，免疫调节治疗显着有效。