Abstract
AIMS: Myocarditis and pericarditis have been proposed to account for a proportion of cardiac injury during SARS-CoV-2 infection. During the COVID-19 pandemic, it is reasonable to expect an increasing trend in incidence of this acute inflammatory cardiac diseases. To examine the incidence and prevalence of inflammatory heart disorders prior to and during the COVID-19 pandemic. METHODS AND RESULTS: This is a retrospective cohort study examining the incidence and prevalence of acute inflammatory heart diseases (myocarditis, pericarditis) in provinces of Pisa, Lucca and Livorno (total population of 11421285 inhabitants) in two time-intervals: (i) prior to (PRECOVID, from 1 June 2018 to 31 May 2019) and (ii) during the COVID-19 pandemic (COVID, from 1 June 2020 to May 2021). 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 PRECOVID, 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 acute myocarditis was significantly higher in PRECOVID than in the COVID: respectively, 8.1/100 000/year vs. 5.9/100 000 year (P = 0.047), consisting in 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 (P = 0.048) (Figure). The annual incidence of pericarditis was not significantly different (4.03/100 000 vs. 4.47/100 000; P = 0.61). CONCLUSIONS: Despite a possible etiologic role of SARS-CoV-2 and an expectable increased incidence of myocarditis and pericarditis, data suggest a decrease of acute myocarditis and a stable incidence pericarditis and both diseases. [Image: see text]