Overwhelmingly likely to be unrelated: https://www.nationalgeographic.com/science/article/the-real-... (https://archive.li/0QXCj)

...and, from the study you link to:

> mRNA-1273 vaccine-associated myocardial injury was more common than previously thought, being mild and transient, and more frequent in women versus men.

"Mild and transient" does not describe a heart attack.