You're probably a "lean mass hyper-responders", a phenotype which is actively investigated, initial paper:

Elevated LDL-cholesterol levels among lean mass hyper-responders on low-carbohydrate ketogenic diets deserve urgent clinical attention and further research

https://pubmed.ncbi.nlm.nih.gov/36351849/

A few other more recent papers:

https://pubmed.ncbi.nlm.nih.gov/35498420/

https://www.jacc.org/doi/10.1016/j.jacadv.2024.101109

Note: I'm not a doctor.

Seems a bit unfair sometimes how arbitrary genetics can be. I've fought my weight all my life, only recently achieving consistent success with the assistance of GLP1s. I can't claim to be consistent with exercise either. Yet my numbers are great, I've done some of these deeper tests and everything comes back beautiful. My parents were overweight their whole life and both lived deep into their 80s (and my dad only died because he got an unlucky gall bladder infection and then ignored all the rapidly accumulating evidence that he was getting quite sick; he'd have gone another few years most likely). I don't recall anyone in my immediate ancestors having a heart attack. Seems it's just not in our genetics.

My father-in-law is more like you. Athletic, skinny, been that way all his life. Heart attack and quad bypass in his 40s.

They have me on blood pressure meds and do the usual blood tests, the tests I considered have been elective and I requested them explicitly. Just haven’t followed through due to aforementioned hesitations. I’m very much aware heart issues run in the family and that I have symptoms.

But I would be very happy to do any elective non invasive tests. On the fence about going beyond that until/unless the Dr. flags it as needed.