Objective

Despite growing evidence about myocardial injury in hospitalized COronaVIrus Disease 2019 (COVID-19) patients, the mechanism behind this injury is only poorly understood and little is known about its association with SARS-CoV-2-mediated myocarditis. Furthermore, definite evidence of the presence and role of SARS-CoV-2 in cardiomyocytes in the clinical scenario is still lacking.

Methods

We histologically characterized myocardial tissue of 40 patients deceased with severe SARS-CoV-2 infection during the first wave of the pandemic. Clinical data were also recorded and analyzed. In case of findings supportive of myocardial inflammation, histological analysis was complemented by RT-PCR and immunohistochemistry for SARS-CoV-2 viral antigens and in situ RNA hybridization for the detection of viral genomes.

Results

Both chronic and acute myocardial damage was invariably present, correlating with the age and comorbidities of our population. Myocarditis of overt entity was found in one case (2.5%). SARS-CoV-2 genome was not found in the cardiomyocytes of the patient with myocarditis, while it was focally and negligibly present in cardiomyocytes of patients with known viral persistence in the lungs and no signs of myocardial inflammation. The presence of myocardial injury was not associated with myocardial inflammatory infiltrates.

Conclusions

In this autopsy cohort of COVID-19 patients, myocarditis is rarely found and not associated with SARS-CoV-2 presence in cardiomyocytes. Chronic and acute forms of myocardial damage are constantly found and correlate with the severity of COVID-19 disease and pre-existing comorbidities.

Graphic abstract

中文翻译：

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SARS-CoV-2、心肌损伤和炎症：来自大型临床和尸检研究的见解

客观的

尽管越来越多的证据表明 2019 年冠状病毒病 (COVID-19) 住院患者的心肌损伤，但人们对这种损伤背后的机制知之甚少，对其与 SARS-CoV-2 介导的心肌炎的关联知之甚少。此外，在临床情况下，仍然缺乏关于 SARS-CoV-2 在心肌细胞中存在和作用的明确证据。

方法

我们对第一波大流行期间死于严重 SARS-CoV-2 感染的 40 名患者的心肌组织进行了组织学表征。临床数据也被记录和分析。在发现支持心肌炎症的情况下，组织学分析通过 RT-PCR 和 SARS-CoV-2 病毒抗原的免疫组织化学和用于检测病毒基因组的原位 RNA 杂交来补充。

结果

慢性和急性心肌损伤总是存在，与我们人群的年龄和合并症相关。1例（2.5%）发现明显实体性心肌炎。在心肌炎患者的心肌细胞中未发现 SARS-CoV-2 基因组，而在已知病毒在肺部持续存在且没有心肌炎症迹象的患者的心肌细胞中，它的存在可忽略不计。心肌损伤的存在与心肌炎性浸润无关。

结论

在这个 COVID-19 患者的尸检队列中，很少发现心肌炎，并且与心肌细胞中 SARS-CoV-2 的存在无关。不断发现慢性和急性心肌损伤形式，并与 COVID-19 疾病的严重程度和先前存在的合并症相关。

图形摘要