Yes, rare for an athlete.
My doc says genetics play a large role. Some could eat celery sticks 24/7 and still suffer heart disease. Apparently O'Leary falls in that group. Also, those of Irish descent appear more susceptible to heart disease. The good news: if caught early, statin drugs are effective.
Heart treatment is amazing these days. O'Leary back in 2021 is not unreasonable.