After receiving the new Pfizer Bivalent booster in November, 2022 (the 5th in the series I've received to date) I experienced an episode of what was diagnosed as "new-onset" A-fib (flagged by the Apple watch I was wearing), approximately 2 months after receiving the booster. During the period I was experiencing it, the watch recorded 3 episodes during the course of the day. Not knowing the potential impact or significance of the episodes I went to my Hospital ER, after the 3rd was signaled, where the ER physician confirmed it was A-fib following a 6 hour monitoring period. He described it as being "in-control" in that the upper limit heart rate never exceeded 90 bpm. My cardiologist, who I saw the next day, attributed this to the fact that, as a cardiac patient (heart attack in 2014), I was taking the beta blocker Carvedilol. The ER physician prescribed Eliquis, which I started immediately, to address the potential stroke risk associated with A-fib. My concern, did I experence milder A-fib episodes earlier that my watch or I did not recognize as such, and how many individuals are having them and not reporting them because they don't recognize them for what they are. My other question, as a 77 year old heart patient, should I take the 2023 vaccine booster?