Yeah, this is uncommon but it does happen in high school, maybe even college. You rarely hear of it in professional football because they are having a lot of testing done prior to being paid millions of dollars. People valiantly defending pfizer can deflect/lie all they want, there have never been this many heart related issues in athletes in this short of a time span in the past 60-70 years. Probably not even then but there isn't detailed recording of that.