Pathological Anatomy, Department of Cardiac, Thoracic and Vascular Sciences, University of Padua Medical School, Via A. Gabelli, 61, 35121, Padua, Italy,
Heart Fail Rev. 2013 Nov;18(6):673-81. doi: 10.1007/s10741-012-9355-6.
In the WHO 1996 classification of cardiomyopathies, myocarditis is defined as an "inflammatory disease of the myocardium associated with cardiac dysfunction" and is listed among "specific cardiomyopathies". Myocarditis is diagnosed on endomyocardial biopsy (EMB) by established histological, immunological, and immunohistochemical criteria, and molecular techniques are recommended to identify viral etiology. Infectious, autoimmune, and idiopathic forms of inflammatory cardiomyopathy are recognized that may lead to dilated cardiomyopathy. According to Dallas criteria, myocarditis is diagnosed in the setting of an "inflammatory infiltrate of the myocardium with necrosis and/or degeneration of adjacent myocytes, not typical of ischemic damage associated with coronary artery disease". The majority of experts in the field agree that an actual increase in sensitivity of EMB has now been reached by using immunohistochemistry together with histology. A value of >14 leukocytes/mm(2) with the presence of T lymphocytes >7 cells/mm(2) has been considered a realistic cut off to reach a diagnosis of myocarditis. The development of molecular biological techniques, particularly amplification methods like polymerase chain reaction (PCR) or nested-PCR, allows the detection of low copy viral genomes even from an extremely small amount of tissue such as in EMB specimens. Positive PCR results obtained on EMB should always be accompanied by a parallel investigation on blood samples collected at the time of the EMB. According to the recent Association for European Cardiovascular Pathology guidelines, optimal specimen procurement and triage indicates at least three, preferably four, EMB fragments, each 1-2 mm in size, that should immediately be fixed in 10 % buffered formalin at room temperature for light microscopic examination. In expected focal myocardial lesions, additional sampling is recommended. Moreover, one or two specimens should be snap-frozen in liquid nitrogen and stored at -80 °C or alternatively stored in RNA-later for possible molecular tests or specific stains. A sample of peripheral blood (5-10 ml) in EDTA or citrate from patients with suspected myocarditis allows molecular testing for the same viral genomes sought in the myocardial tissue.
在世界卫生组织 1996 年的心肌病分类中，心肌炎被定义为“心肌的炎症性疾病，伴有心功能障碍”，并被列为“特定心肌病”之一。心肌炎通过组织学、免疫学和免疫组织化学标准的心肌内膜活检（EMB）进行诊断，建议采用分子技术来确定病毒病因。已识别出感染性、自身免疫性和特发性炎症性心肌病，它们可能导致扩张型心肌病。根据达拉斯标准，当“心肌炎症浸润伴有心肌细胞坏死和/或变性，而不是与冠状动脉疾病相关的缺血性损伤的典型表现”时，诊断为心肌炎。该领域的大多数专家都认为，通过使用免疫组织化学与组织学相结合，现在已经达到了 EMB 的实际灵敏度提高。认为白细胞计数>14/毫米^2，且 T 淋巴细胞计数>7/毫米^2是诊断心肌炎的一个现实的截断值。分子生物学技术的发展，特别是聚合酶链反应（PCR）或巢式-PCR 等扩增方法，允许即使从 EMB 标本等极少量组织中检测到低拷贝数的病毒基因组。在 EMB 上获得的阳性 PCR 结果应始终伴随同时对 EMB 采集时收集的血液样本进行平行研究。根据最近的欧洲心血管病理学协会指南，最佳标本采集和分类指示至少采集三个，最好是四个，每个 1-2 毫米大小的 EMB 片段，这些片段应立即在室温下用 10%缓冲福尔马林固定，以便进行光镜检查。在预期的局灶性心肌病变中，建议进一步取样。此外，建议对一个或两个标本进行快速冷冻在液氮中，并在-80°C 下储存，或者在 RNA 后储存，以备可能进行分子检测或特定染色。从疑似心肌炎患者中采集的 5-10 毫升 EDTA 或柠檬酸盐抗凝血的外周血样本允许对心肌组织中寻找的相同病毒基因组进行分子检测。
