Cardiac Safety of COVID-19 Vaccines

Background: The aim of this study was to assess myocardial metabolic activity and cardiac function in asymptomatic health checkup subjects before and after COVID-19 vaccination.Methods: We retrospectively analyzed clinical records of 67 asymptomatic subjects who underwent whole-body 18 F-fluorodeoxyglucose (FDG) positron emission tomography / computed tomography before and after COVID-19 vaccination.Cardiac metabolic activity was assessed using myocardial standardized uptake value (SUVmax).Echocardiography and cardiac magnetic resonance imaging (MRI), including cine-based strain analysis, were used to evaluate cardiac function.The Wilcoxon signed-rank test and Bland-Altman plots were applied to assess changes between pre-and post-vaccination data.Results: No significant differences in myocardial FDG uptake (SUVmax: 3.29 [interquartile ranges : 2.84-6.45]vs. 3.21 [IQR: 2.76-7.25],P=0.63) was observed.Similarly, echocardiographic parameters, including left ventricular ejection fraction, left ventricular end-diastolic volume, and left ventricular end-systolic volume, remained unchanged.MRI-based circumferential strain also showed no significant alterations (-21.27±3.63 vs. -21.90±3.60,P=0.088).Conclusions: This study, the first to systematically evaluate myocardial FDG uptake alongside MRI strain analysis in the same subjects pre-and post-vaccination, suggests that vaccination is not associated with meaningful changes in myocardial metabolic activity or cardiac function.These findings lend support to the cardiac safety of COVID-19 vaccination and provide a robust basis for future research in broader populations.