Syncope With Sinus Arrest Following a Single Dose of a COVID-19 Vaccine.

Vaccines against the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) are of paramount importance in combating the current coronavirus disease 2019 (COVID-19) pandemic. Syncopal episodes following routine vaccinations are well-reported; however, only a few cases of syncope following SARS-CoV-2 vaccines exist in the literature. This is a case report of a 21-year-old female patient who developed recurrent syncopal attacks over three months that started one day after receiving the first dose of the Pfizer-BioNTech COVID-19 vaccine (Pfizer, New York City; BioNTech, Mainz, Germany). Holter monitoring during successive episodes showed progressive bradycardia followed by a prolonged sinus arrest. The patient eventually required pacemaker placement that resulted in the total resolution of her symptoms. Further studies are required to investigate a possible correlation and the mechanisms involved.