In this study, we aimed to characterize the clinical presentation, short-term prognosis, and myocardial tissue changes as noted on cardiovascular magnetic resonance (CMR) or cardiac MRI in pediatric patients with coronavirus disease 2019 vaccination-associated myocarditis (C-VAM).

In this retrospective multicenter study across 16 US hospitals, patients <21 years of age with a diagnosis of C-VAM were included and compared with a cohort with multisystem inflammatory syndrome in children. Younger children with C-VAM were compared with older adolescents.

Sixty-three patients with a mean age of 15.6 years were included; 92% were male. All had received a messenger RNA vaccine and, except for one, presented after the second dose. Four patients had significant dysrhythmia; 14% had mild left ventricular dysfunction on echocardiography, which resolved on discharge; 88% met the diagnostic CMR Lake Louise criteria for myocarditis. Myocardial injury as evidenced by late gadolinium enhancement on CMR was more prevalent in comparison with multisystem inflammatory syndrome in children. None of the patients required inotropic, mechanical, or circulatory support. There were no deaths. Follow-up data obtained in 86% of patients at a mean of 35 days revealed resolution of symptoms, arrhythmias, and ventricular dysfunction.

Clinical characteristics and early outcomes are similar between the different pediatric age groups in C-VAM. The hospital course is mild, with quick clinical recovery and excellent short-term outcomes. Myocardial injury and edema are noted on CMR. Close follow-up and further studies are needed to understand the long-term implications and mechanism of these myocardial tissue changes.

在本研究中，我们旨在表征 2019 年冠状病毒病疫苗接种相关性心肌炎 (C-VAM) 儿童患者的心血管磁共振 (CMR) 或心脏 MRI 所记录的临床表现、短期预后和心肌组织变化。

在这项横跨 16 家美国医院的回顾性多中心研究中，纳入了诊断为 C-VAM 的 21 岁以下患者，并与儿童多系统炎症综合征队列进行了比较。将患有 C-VAM 的年幼儿童与年龄较大的青少年进行比较。

包括 63 名平均年龄为 15.6 岁的患者；92% 是男性。所有人都接受了信使 RNA 疫苗，除了一个，在第二剂后接种。4 名患者有明显的心律失常；14% 的超声心动图显示轻度左心室功能障碍，出院后缓解；88% 符合诊断 CMR 路易斯湖心肌炎的标准。与儿童多系统炎症综合征相比，CMR 上钆晚期增强所证明的心肌损伤更为普遍。没有患者需要正性肌力、机械或循环支持。没有死亡。86% 的患者在平均 35 天后获得的随访数据显示症状、心律失常和心室功能障碍得到缓解。

C-VAM 中不同儿科年龄组的临床特征和早期结果相似。住院过程温和，临床恢复快，短期效果好。在 CMR 上观察到心肌损伤和水肿。需要密切随访和进一步研究以了解这些心肌组织变化的长期影响和机制。