HI, I'm so so sorry to hear of your loss. I know how hard it is. I think you needed a post mortem to establish cause of death. It would be very rare for someone to have all those tests and fall through the net as being normal.
Sorry to hear that!
Since that happened to him, you want to make sure it doesn't happen to you so do like me: walk 30 minutes about 5 times a week-DO NOT RUN, take fish pills, Magnesium, Vitamin c, vitamin k2, 1 or 2 cayenne capsules, other supplements and consider a statin. Statins are not a sure thing since most people have normal cholesterol levels-below 200- when they suffer a heart attack. There are other herbs and supplements that affect blood coagulation so be careful if you add them to fish oil because they all add upon the other.
Your father could have gotten a clot that blocked an artery in the heart.......There are many people getting blood clots in legs, lungs, etc., and they are lucky. Another thing that I believe happens is that if you are Experiencing CRAMPS, then you are at Risk of getting a cramp in a cardiac artery or muscle. You do not want this to happen so make sure you supplement magnesium, use Epsom salt in your baths, or eat as much raw, green vegetables like spinach! Anytime you see cardiac arrest it means that there was most likely a problem with the electrical activity of the heart and not HEART ATTACK-blood clot. I have no clue how many people die of heart attack or arrest but believe quite a few of them have no blockage of blood in their hearts............I am NO doctor, but I trust my brain better than anyone else's!
My condolences. I wish the result were different for you. Plse take care of yourself now. mary