COVID-19 myocarditis

Background: Myocarditis can be observed in patients with COVID-19. Myocarditis can also be seen in patients vaccinated against SARS-CoV-2 infection, the etiological agent of this disease. Epidemiological, morphological, pathophysiological, clinical aspects, clinical course, and potential therapeutics for patients with COVID-19 myocarditis are not entirely clear.
Methods: We perform a search in PubMed linking the terms “COVID-19 and myocarditis”, “SARS-CoV-2 and myocarditis”, and “vaccine and myocarditis and COVID-19”. A hand-search of references from retrieved papers has also been done. We selected papers dealing with the epidemiological, morphological, clinical aspects, and therapeutic regarding COVID-19 myocarditis.
Results: Myocarditis can be clinically diagnosed in about 2% of patients with COVID-19 illness, but its prevalence is higher (up to 33%) in autopsied with this disease. At magnetic resonance imaging, myocarditis can be diagnosed in up to 60% patients in the short-term follow up after SARS-CoV-2 infection. A few ultrastructural studies have detected SARS-CoV-2 in endothelial cells, macrophages, neutrophils, fibroblasts, and inside cardiomyocytes. Shortness of breath, fever, cough, and precordial chest pain are the main clinical symptoms; in half patients, ground glass opacities in chest X-ray are also observed, although oxygen saturation may be normal. COVID-19 myocarditis may occur in a patient with no past cardiac history and may alternatively be a late phenomenon in the course of the disease. COVID-19 myocarditis can also affect children and adolescents; acute heart failure is the predominant clinical manifestation, including fulminant myocarditis, in this population. Elevated troponin blood levels are observed in the majority of patients. Abnormal electrocardiogram findings – usually ST-segment changes and inverted T waves – can be detected in at least 25% of cases. Abnormal echocardiography can be found in 3% of cases and left ventricular systolic dysfunction can be found in 67% of such cases. The clinical course of COVID-19 myocarditis is usually benign with most patients recovering from the myocardial insult. Non-steroidal anti-inflammatory drugs are the treatment for noncomplicated cases; colchicine is added in case of associated pericarditis. Corticosteroids have largely been used. Mechanical support is lifesaving in cases of cardiogenic shock. Post-vaccination myocarditis is very rare, and less frequently found than COVID-19 myocarditis.
Conclusions: Although relative rare, myocarditis may be a serious complication of COVID-19 illness.