Clinical and morphological characteristics of COVID-19-associated myocarditis

Abstract

Background: COVID-19 is accompanied by the development of a wide range of cardiovascular lesions. The goal: to study the clinical and morphological features of SARS-CoV-2-associated myocarditis (SCM), determining the presence of viral RNA and proteins in myocardial tissue. Methods: The study was based on 32 autopsies with a confirmed diagnosis of myocarditis. The average age of the patients was 72.7±15.5 years. Men predominated in the group (53%). The immunohistochemical determination of the surface markers of CD45, CD3, CD20, CD 68 inflammatory infiltrates and SARS-CoV-2 nucleocapsid and spike protein has been done. Detection of coronavirus RNA was performed. Results: The clinical manifestations SCM included heart failure and variety of rhythm disturbances. Increased level of anticardiac antibodies was detected. Lymphomacrophage infiltrates (more than 7 CD3+ T-lymphocytes, more than 14 CD45+ lymphocytes and more than 7 CD68+ macrophages per 1 mm2) were found in 100% of cases. RNA of the virus was detected in myocardial tissue. Virus proteins were identified in macrophages of the inflammatory infiltrate and cardiomyocytes. Conclusion: The results suggest persistence of the virus.