Not sure about a trigger, but I would check troponin level immediately after getting the vaxx, and then keep an eye on various markers of inflammation like C-reactive protein after that. There’s still a lot of unknowns about this, but anybody who has been following the research on pubmed knows that this vaxx is likely very risky over both the short and long term.
With the uptake rate cratering, the vaxxes have got to be doing far more long term damage than anyone has admitted.