Myocarditis during SARS-CoV-2 Infection: A Series of 15 Cases

COVID-19 is a global health problem responsible for significant morbidity and mortality and a major socioeconomic impact. While the major manifestation is respirator with a risk of acute respiratory distress syndrome, several extrapulmonary aspects, particularly cardiovascular, have emerged over time.

The aim of this work is to study the clinical, biological, radiological, therapeutic, and evolutionary characteristics of acute myocarditis associated with SARS-CoV-2 infection in comparison to data from the literature.

This is a prospective cohort study conducted at the Ibn Sina University Hospital in Rabat over a period of 9 months (from January 1, 2021, to September 30, 2021) and included patients hospitalized in different departments managing COVID-19 and diagnosed with acute myocarditis confirmed by cardiac MRI.

Fifteen patients were included during the study period. The average age of patients was 40 years old with a slight male predominance (sex ratio M/F-1.14). The average time between the onset of COVID-19 infection and the appearance of myocarditis symptoms was 17 days. The symptoms were mainly dominated by chest pain (40% of cases), unexplained cardiogenic shock (40% of cases), and palpitations (20% of cases). ECG revealed diffuse repolarization abnormalities in more than half of the cases (53%) and supraventricular tachycardia (27%). The inflammatory markers were significantly disturbed (CRP = 102 +/-47.30 mg/L and ferritin - 510 +/-336.45 ng/mL). Troponin I was elevated with myocarditis kinetics in all patients. Cardiac MRI showed T2 hypersignal corresponding to edema with early and late subepicardial enhancement, mainly located at the level of the left ventricular lateral wall.

The evolution was marked by the occurrence of death in 5 patients (33.33%) in the days following hospitalization for cardiogenic shock and dilated cardiomyopathy in only one case (6.67%). It was favourable for the rest of the patients (60%).

The results of this study have highlighted several characteristics of myocarditis associated with SARS-CoV-2. Firstly, there is a delayed interval between virus infection and the onset of cardiac symptoms. Additionally, the kinetics of myocardial injury markers are distinct, and there is significant disruption of inflammatory markers at the time of diagnosis. Moreover, fulminant forms of myocarditis are associated with a reserved prognosis and high mortality.

Furthermore, the study emphasizes the crucial importance of cardiac MRI availability for confirming the diagnosis in the absence of histological evidence from endomyocardial biopsy.