Mt wife is 70 years old and received a Pfizer booster shot in late November. She woke up the next morning with her heart rate increased dramatically. She is was in good physical condition with normal heart rate (high 50's to low 60's) and normal blood pressure prior to getting the shot. I took her to see the doctor and her heart rate was in the 80's. It has been over a month and the problem has not improved. It may even be worse. We have measured her heart rate go as high as 112.