Hospitalization Due to Acute Coronary Syndrome and Myocarditis in Patients Under 45 Years Old: A Single-Center Coronary Care Unit Retrospective Documentation of Hospitalizations Before, During, and After the COVID-19 Pandemic

OBJECTIVE
It is still controversial whether COVID-19 infection and vaccination may cause acute coronary syndrome (ACS) and myocarditis, especially in young adults. The aim of this study was to explore the hospitalization rates of ACS and myocarditis in patients under 45 years of age during the pre-pandemic, pandemic, and post-pandemic periods.

METHODS
This retrospective, single-center study included 944 patients under 45 years of age who were admitted to coronary care unit with the diagnosis of ACS or myocarditis. The patients were grouped into three according to their admission times as pre-pandemic group (January 2019 and 31 March 2020), pandemic group (1 April 2020 and 30 September 2022) and post-pandemic group (1 October 2022 and 31 December 2023).

RESULTS
There were not any significant differences in the ratios of the patients under 45 years old to the overall coronary care admissions among the groups (12.9% vs 11.0% vs 11.8% respectively, p= 0.134). Similarly, although there was a slight increase in the ratio of myocarditis over ACS among the groups, the difference was not significant (29.9% vs 70.1%, 32.0% vs 68.0% and 34.2% vs 65.8% respectively, p=0.600). The myocarditis rate was comparable between vaccinated and unvaccinated patients, with no significant differences observed based on vaccine types.

CONCLUSION
The hospitalization rates for ACS and myocarditis in our center were similar for patients under the age of 45 years among prepandemic, pandemic and postpandemic periods; which supported the studies showing no association of COVID-19 infection and vaccination with ACS and myocarditis. However, this study reflects single-center documentation of hospitalized ACS and myocarditis cases, and does not provide data on overall incidence, prevalence, or causal relationships between these conditions and the pandemic.