Myocarditis--a frequent cause of dilated cardiomyopathy and sudden cardiac death--typically results from cardiotropic viral infection followed by active inflammatory destruction of the myocardium. Characterization of this disease has been hampered by its heterogeneous clinical presentations and diverse aetiologies. Advances in cardiac MRI and molecular detection of viruses by endomyocardial biopsy have improved our ability to diagnose and understand the pathophysiological mechanisms of this elusive disease. However, therapeutic options are currently limited for both the acute and chronic phases of myocarditis. Several randomized, controlled trials have demonstrated potential benefit with immunosuppressive and immunomodulatory therapies, but further investigations are warranted. In this Review, we explore the pathophysiology, natural history, and modes of diagnosis of myocarditis, as well as evidence-based treatment strategies. As novel imaging techniques and human in vitro models of the disease emerge, the landscape of therapies for myocarditis is poised to improve.

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BACKGROUND Myocarditis is inflammation of the heart muscle that can follow various viral infections. Why children only rarely develop life-threatening acute viral myocarditis (AVM), given that the causal viral infections are common, is unknown. Genetic lesions might underlie such susceptibilities. Mouse genetic studies demonstrated that interferon- (IFN) α/β immunity defects increased susceptibility to virus-induced myocarditis. Moreover, variations in human TLR3, a potent inducer of IFNs, were proposed to underlie AVM. OBJECTIVES We evaluated the hypothesis that human genetic factors might underlie AVM in previously healthy children. METHODS We tested the role of TLR3-IFN immunity utilizing human-induced pluripotent stem cell-derived cardiomyocytes. We then performed whole exome sequencing of 42 unrelated children with acute myocarditis (AM), some with proven viral etiologies. RESULTS We found that TLR3- and STAT1-deficient cardiomyocytes were not more susceptible to coxsackievirus B3 (CVB3) infection than control cells. Moreover, CVB3 did not induce IFN-α/β and IFN-α/β-stimulated genes in control cardiomyocytes. Finally, exogenous IFN-α did not substantially protect cardiomyocytes against CVB3. We did not observe a significant enrichment of rare variations in TLR3- or IFN-α/β-related genes. Surprisingly, we found that homozygous, but not heterozygous, rare variants in genes associated with inherited cardiomyopathies were significantly enriched in AM-AVM patients compared with healthy individuals (p = 2.22E-03) or patients with other diseases (p = 1.08E-04). Seven of 42 patients (16.7%) carried rare biallelic nonsynonymous or splice-site variations in 6 cardiomyopathy-associated genes (BAG3, DSP, PKP2, RYR2, SCN5A, or TNNI3). CONCLUSIONS Previously silent recessive defects of the myocardium may predispose to acute heart failure presenting as AM, notably after common viral infections.

Survivors of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) infection frequently experience lingering neurological symptoms, including impairment in attention, concentration, speed of information processing and memory. This long-COVID cognitive syndrome shares many features with the syndrome of cancer therapy-related cognitive impairment (CRCI). Neuroinflammation, particularly microglial reactivity and consequent dysregulation of hippocampal neurogenesis and oligodendrocyte lineage cells, is central to CRCI. We hypothesized that similar cellular mechanisms may contribute to the persistent neurological symptoms associated with even mild SARS-CoV-2 respiratory infection. Here, we explored neuroinflammation caused by mild respiratory SARS-CoV-2 infection, without neuroinvasion, and effects on hippocampal neurogenesis and the oligodendroglial lineage. Using a mouse model of mild respiratory SARS-CoV-2 infection induced by intranasal SARS-CoV-2 delivery, we found white matter-selective microglial reactivity, a pattern observed in CRCI. Human brain tissue from 9 individuals with COVID-19 or SARS-CoV-2 infection exhibits the same pattern of prominent white matter-selective microglial reactivity. In mice, pro-inflammatory CSF cytokines/chemokines were elevated for at least 7-weeks post-infection; among the chemokines demonstrating persistent elevation is CCL11, which is associated with impairments in neurogenesis and cognitive function. Humans experiencing long-COVID with cognitive symptoms (48 subjects) similarly demonstrate elevated CCL11 levels compared to those with long-COVID who lack cognitive symptoms (15 subjects). Impaired hippocampal neurogenesis, decreased oligodendrocytes and myelin loss in subcortical white matter were evident at 1 week, and persisted until at least 7 weeks, following mild respiratory SARS-CoV-2 infection in mice. Taken together, the findings presented here illustrate striking similarities between neuropathophysiology after cancer therapy and after SARS-CoV-2 infection, and elucidate cellular deficits that may contribute to lasting neurological symptoms following even mild SARS-CoV-2 infection.

Introduction: One of the noted features of COVID-19 is the spectrum of expressivity in symptoms among those with the disease, ranging from no or mild symptoms that may last a small number of days, to severe and/or longer lasting symptoms. It is emerging that many patients have long lasting symptoms, several months after initial infection with COVID-19. The aim of this research was to characterize post-acute COVID-19 syndrome (PACS). Methods: This was a retrospective cross-sectional observational study. Participants were patients recovering from COVID-19 infection, enrolled in Mount Sinai Hospital′s COVID-19 Precision Recovery Program (PRP). Inclusion criteria were confirmed or probable (based on World Health Organization criteria) initial diagnosis of COVID-19; post-acute COVID-19 syndrome (defined as experiencing symptoms > 6 weeks since acute symptom onset) and being currently enrolled in the PRP during the months of July and August 2020. Study survey data were collected using REDCap. Demographic data, COVID-19 clinical data and patient-reported outcomes for breathlessness (Medical Research Council Breathlessness Scale), fatigue and quality of life (EuroQoL 5D-5L) were collected. Results: 84 individuals with PACS were included. Symptoms persisted at mean (range) 151 (54 to 255) days. The most prevalent persistent symptoms were fatigue (92%), loss of concentration/memory (74%), weakness (68%), headache (65%) and dizziness (64%). Most participants reported increased levels of disability associated with breathlessness, increased fatigue and reduced quality of life. Conclusions: Persistent symptoms following COVID-19 infection are prevalent, debilitating and appear to affect individuals regardless of acute infection severity or prior health status. More detailed research is required in order to identify specific symptom clusters associated with PACS, and to devise effective interventional strategies.

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Headache and neck pain (cervicalgia) are frequently reported among patients with joint hypermobility but the prevalence and scope of these symptoms has not been studied in the era of contemporary Ehlers-Danlos and hypermobility disorder nosology. We performed a single-center retrospective study on the incidence of head and neck symptoms in 140 patients with hypermobility disorders over a 2-year period. Overall, 93 patients (66%) reported either headache or neck pain with 49 of those (53%) reporting both. Migraine (83%) was the most common headache type among those with headache disorders and cervical spondylosis (61%) the most common pathology among those with neck symptoms. Fifty-nine percent of spondylosis patients who underwent cervical facet procedures reported significant improvement in neck and head symptoms. Of patients with both head and neck complaints, 82% had both migraine and spondylosis, which, when combined with the high response rate to injections raises the possibility of cervicogenic headache. In this large multidisciplinary retrospective study of patients with hypermobility disorders, head and neck symptoms were highly prevalent, with migraine and cervical spondylosis common, often coexisting, and frequently responsive to targeted therapy for the cervical spine suggesting that degenerative spinal pathology may cause or contribute to headache symptoms in some patients with hypermobility disorders.