Aim      Despite the regular heart damage in patients with coronavirus pneumonia caused by SARS-Cov-2, a possibility of developing lymphocytic myocarditis as a part of COVID-19 remains unsubstantiated. The aim of this study was to demonstrate a possibility of lymphocytic myocarditis and to study its morphological features in patients with the novel coronavirus infection (COVID-19) with a severe course.Material and methods   Postmortem data were studied for 5 elderly patients (74.8±4.4 years; 3 men and 2 women) with the novel coronavirus infection and bilateral, severe polysegmental pneumonia (stage 3–4 by computed tomography). COVID-19 was diagnosed based on the typical clinical presentation and positive polymerase chain reaction test in nasopharyngeal swabs. All patients were treated in different hospitals repurposed for the treatment of patients with COVID-19. A standard histological study was performed with hematoxylin and eosin, toluidine blue, and van Gieson staining. Serial paraffin slices were studied immunohistochemically with antibodies to CD3, СD68, CD20, perforin, and toll-like receptors (TLR) 4 and 9.Results In none of the cases, myocarditis was suspected clinically, added to the diagnosis or indicated as a possible cause of death. IHD and acute myocardial infarction were mentioned as error diagnoses not confirmed by the postmortem examination. The morphological examination of the heart identified signs of lymphocytic myocarditis consistent with Dallas criteria for this diagnosis. Myocardial infiltrate was characterized in detail, and a combined inflammatory damage of endocardium and pericardium was described. The immunohistochemical study with cell infiltrate typing confirmed the presence of CD3-positive Т lymphocytes and the increased expression of TLR-4. A picture of coronaritis, including that with microvascular thrombosis, was found in all cases.Conclusion      A possibility for development of lymphocytic viral myocarditis in COVID-19 was confirmed morphologically and immunohistochemically. Specific features of myocarditis in COVID-19 include the presence of coronaritis and a possible combination of myocarditis with lymphocytic endo- and pericarditis.

Aims Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality. Methods and results We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable Poisson regression models were fitted to assess the association between different types of pre-existing heart disease and in-hospital mortality. A total of 16 511 patients with COVID-19 were included (21.1% aged 66–75 years; 40.2% female) and 31.5% had a history of heart disease. Patients with heart disease were older, predominantly male, and often had other comorbid conditions when compared with those without. Mortality was higher in patients with cardiac disease (29.7%; n = 1545 vs. 15.9%; n = 1797). However, following multivariable adjustment, this difference was not significant [adjusted risk ratio (aRR) 1.08, 95% confidence interval (CI) 1.02–1.15; P = 0.12 (corrected for multiple testing)]. Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for heart failure (aRR 1.19, 95% CI 1.10–1.30; P < 0.018) particularly for severe (New York Heart Association class III/IV) heart failure (aRR 1.41, 95% CI 1.20–1.64; P < 0.018). None of the other heart disease subtypes, including ischaemic heart disease, remained significant after multivariable adjustment. Serious cardiac complications were diagnosed in <1% of patients. Conclusion Considerable heterogeneity exists in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with heart failure are at greatest risk of death when hospitalized with COVID-19. Serious cardiac complications are rare during hospitalization.

Aims Patients with cardiac disease are considered high risk for poor outcomes following hospitalization with COVID-19. The primary aim of this study was to evaluate heterogeneity in associations between various heart disease subtypes and in-hospital mortality. Method and results We used data from the CAPACITY-COVID registry and LEOSS study. Multivariable modified Poisson regression models were fitted to assess the association between different types of pre-existent heart disease and in-hospital mortality. 10,481 patients with COVID-19 were included (22.4% aged 66-75 years; 38.7% female) of which 30.5% had a history of cardiac disease. Patients with heart disease were older, predominantly male and more likely to have other comorbid conditions when compared to those without. COVID-19 symptoms at presentation did not differ between these groups. Mortality was higher in patients with cardiac disease (30.3%; n=968 versus 15.7%; n=1143). However, following multivariable adjustment this difference was not significant (adjusted risk ratio (aRR) 1.06 [95% CI 0.98-1.15, p-value 0.13]). Associations with in-hospital mortality by heart disease subtypes differed considerably, with the strongest association for NYHA III/IV heart failure (aRR 1.43 [95% CI 1.22-1.68, p-value <0.001]) and atrial fibrillation (aRR 1.14 [95% CI 1.04-1.24, p-value 0.01]). None of the other heart disease subtypes, including ischemic heart disease, remained significant after multivariable adjustment. Conclusion There is considerable heterogeneity in the strength of association between heart disease subtypes and in-hospital mortality. Of all patients with heart disease, those with severe heart failure are at greatest risk of death when hospitalized with COVID-19.