The most common cause of myocarditis is viral infection, especially from cardiotropic viruses (Parvovirus B19, Human Herpesvirus 6 and Coxsackie) resulting in a destruction of the myocardium. Moreover, a serological analysis is not systematic and their value remains unclear. The objectives of this study were to assess the viral serology of the patients with acute myocarditis and the relation with clinical and CMR parameters at the acute phase and at distance.

All cases of infarct-like acute myocarditis confirmed by CMR from April 2012 to January 2018 were included in a prospective study at Dijon University Hospital. A blood sampling including viral serology is obtained at the moment of the diagnostic. One-year follow-up included a complete clinical and rhythmic evaluation, and a CMR control.

Among the patients with “infarct like” acute myocarditis, serological analyses were performed in 62 patients and cardiotropic viruses are found in 29 patients. No statistical difference was observed regarding demographic and clinical parameters. However, concerning CMR parameters, the extent of myocarditis is more important in the “cardiotropic viruses” group at the acute phase (10.4 vs. 7.3 – P=0.05) and at three months (6.3 vs. 2.7 – P=0.007) compared to the “no cardiotropic viruses” group. At one year, there was no significant difference between the two groups regarding CMR parameters.

Cardiotropic viruses (HHV6, Parvovirus B19 and Coxsackie virus) were found in almost 50% of cases in “infarct like” acute myocarditis. According the presence or absence of cardiotropic viruses, CMR parameters were different. Furthermore, use of quantitative PCR (detection of viral genomes) or detection of viral DNA and RNA via in situ hybridization would be a challenge for the future identification of viruses in myocarditis.