Reduced MHR due to anaphylaxis?

Hi folks,

Suspect this might be a bit niche, but hoping there might be an STW forumer who can enlighten me.

I had 6 months off the bike 2nd half of 2022, due to tibial plateau fracture surgery. They had to do some revision surgery for the metalwork in Nov, and I had a grade 3 anaphylaxis in pre-op before they could get that sorted, but they got me back pretty quickly with adrenalin and stuff. They were able to finally complete the surgery in December .

I am back on the bike since Jan and getting fit again, but wondering if the anaphylaxis might have some longer term impact on my heart health, or whether it's just time off the bike. I am struggling to get to my previous MHR either on the turbo (really difficult) but also outdoor hill sessions when I used to be able to get to my MHR.

If there is a potential impact on cardio health, do i need to recalibrate my zones? My recovery scores are saying I am not maxing out, even after hard sessions.
And also, if there is a possibility of some cardiac issues, should i get a referral to a heart doc to get an assessment.

TIA