Ive seen a slight heart murmur walk out, mis-diagnosed as "just getting on a bit", and have a fatal infarct getting out of the cockpit 3 hours later
It is more than possible to have a complete heart check-up and investigations with a cardiologist, get a 100% all clear, and then drop dead outside the consulting room door from a heart attack, so I wouldn't jump to conclusions here.
QDM