I was born with a bicuspid aortic valve. Basically, a normal valve has three flaps, and in my case two of them fused together which doesn't allow the valve to seal so the blood leaks back down into my heart. With the tests they did last week they determined that I've reached 33% leakage, which means every time my heart beats 1/3 of the blood it would normally pump doesn't go anywhere.

I went 42 years until I was diagnosed, and another 7 before they decided that it's now leaking bad enough that I can't push off the surgery any longer. This actually turned out for the better as now they can replace the valve with a mechanical one, and while it's major surgery it's fairly routine. Had the valve started leaking 40 years ago, at that time all they could have done would be to tell me to go home and write a will.