Incidence of acute myocarditis and pericarditis during the coronavirus disease 2019 pandemic: comparison with the prepandemic period.

BACKGROUND

Myocarditis and pericarditis have been proposed to account for a proportion of cardiac injury during SARS-CoV-2 infection. The impact of COVID-19 the pandemic on the incidence of this acute inflammatory cardiac disease was not systematically evaluated.

AIM

To examine the incidence and prevalence of inflammatory heart disorders prior to and during the COVID-19 pandemic.

METHODS

We compared the incidence and prevalence of acute inflammatory heart diseases (myocarditis, pericarditis) in the provinces of Pisa, Lucca and Livorno in two time intervals: prior to (PRECOVID, from 1 June 2018 to 31 May 2019) and during the COVID-19 pandemic (COVID, from 1 June 2020 to May 2021).

RESULTS

Overall 259 cases of inflammatory heart disease (myocarditis and/or pericarditis) occurred in the areas of interest. The annual incidence was of 11.3 cases per 100 000 inhabitants. Particularly, 138 cases occurred in the pre-COVID, and 121 in the COVID period. The annual incidence of inflammatory heart disease was not significantly different (12.1/100 000 in PRECOVID vs 10.3/100 000 in COVID, P = 0.22). The annual incidence of myocarditis was significantly higher in PRECOVID than in COVID, respectively 8.1/100 000/year vs. 5.9/100 000/year (P = 0.047) consisting of a net reduction of 27% of cases. Particularly the incidence of myocarditis was significantly lower in COVID than in PRECOVID in the class of age 18-24 years. Despite this, myocarditis of the COVID period had more wall motion abnormalities and greater LGE extent. The annual incidence of pericarditis was, instead, not significantly different (4.03/100 000 vs, 4.47/100 000, P = 0.61).

CONCLUSION

Despite a possible etiologic role of SARS-CoV-2 and an expectable increased incidence of myocarditis and pericarditis, data of this preliminary study, with a geographically limited sample size, suggest a decrease in acute myocarditis and a stable incidence of pericarditis and of myopericarditis/perimyocarditis.