There is data pointing at two possible causes here. The first is neat and politically palatable. Covid increases the risk of heart attack. (https://www.nature.com/articles/d41586-022-00403-0#:~:text=M...).
The second, much more contentious fact is that mRNA vaccines elevate the risk of heart attack. (https://www.bmj.com/content/378/bmj.o1554) In fact, Danish research currently indicates that those who have taken the mRNA vaccines are at greater risk of all-cause mortality. (https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4072489). Note that this paper is currently in peer review. It is receiving more scrutiny than perhaps any other paper in history. There are literally trillions of dollars on the line. Using public, global data, the Danish researcher finds that one is more likely to die after taking the mRNA vaccines, even after accounting for the protective effects against covid. Interview here for those interested (https://unherd.com/thepost/study-into-mrna/).
I think it likely that the increase in heart attacks is a combination of both of these factors.
Disclaimer: I have taken three mRNA vaccines.