Chronic myocarditis as a causative factor that may potentially lead to dilated cardiomyopathy

1.研究发现近年来，临床上引入了左室壁切除术(部分左心室切除术：PLV)来治疗晚期扩张性心力衰竭。在日本，心脏移植仍然与现实不符，扩张型心肌病(DCM)患者应用PLV的指示性标准以及可能影响术后预后的原因仍有待确定。在本研究中，对DCM患者的PLV心肌标本进行了免疫组织化学和病毒学检查。在部分DCM患者心肌标本中可见活动性炎症和持续感染肠道病毒(EV)，提示慢性心肌炎可能是DCM的病因和病理因素之一。EV基因组循环测序显示，检测到的RNA序列大多为柯萨奇B型病毒的序列。这些结果提示，对DCM患者心肌活动性炎症和持续EV感染的病理检测可以预测PLV术后不良的预后。2.展望未来研究我们有能力长期评估DCM患者的术后预后，因为我们已经积累了越来越多的DCM患者接受PLV的临床数据。我们将继续收集DCM患者切除的心肌标本的免疫组织化学和分子生物学分析数据。通过对这些数据的前瞻性预后和实验室检查结果的比较评估，我们希望为扩张型心肌病患者建立一个术前诊断标准，以确定他们是否适合进行PLV。

1.Research findingsRecently, surgical resection of left ventricular wall (partial left ventriculectomy : PLV) was introduced clinically to treat patients with terminal dilated heart failure. In Japan, heart transplantation is yet inconsistent with reality, and indicative standard criteria for applying PLV to patients with dilated cardiomyopathy (DCM), and causative factors that may influence postoperative prognosis remain to be established. In the present study, cardiac muscle specimens obtained at PLV in DCM patients were immunohistochemically and virologically examined. In some DCM patients, active inflammation and persistent infection with enteroviruses (EV) were shown in the cardiac muscle specimens, suggesting that chronic myocarditis may be a causative and pathological factor associated with DCM. Cycle sequencing of EV genome revealed that the RNA sequences detected were mostly those of coxsackie type B viruses. These findings suggested that pathological detection of active inflammation and persistent EV infection of myocardium in DCM patients may predict postoperative poor prognosis after PLV.2.Prospects for the future researchWe are in a position to assess postoperative prognosis of DCM patients in a long-term basis, since we have accumulated clinical data on increasing number of DCM patients who underwent PLV. We will continue to collect data on immunohistochemical and molecular biological analysis of resected myocardium specimens from DCM patients. By comparatively evaluating these data with respect to prospective prognosis and findings on laboratory tests, we hope to establish a preoperative diagnostic standard for DCM patients as to whether they are properly indicated for PLV.