It is extremely rare for teens and early 20’s to have heart attacks. Yet here are 4 recent examples from VAERS:

19 year old, 2 days after vaccination https://www.openvaers.com/covid-data/1077643

21 year old, 4 days after vaccination https://www.openvaers.com/covid-data/1074003

22 year old, 30 mins after vaccination https://www.openvaers.com/covid-data/1046636

21 year old, 1 day after vaccination https://www.openvaers.com/covid-data/994376

Unfortunately, sometimes the results of the jab ar fatal

https://humanevents.com/2021/07/06/michigan-teen-dies-in-his-sleep-days-after-getting-covid-19-vaccine/