Id challenge that. You passed out, we don't know why. well it could be non medical as well.
maybe you worked for 3days straight, maybe you ate something or sat wrong and a nerve pinched. there could be 1001 different things that can cause that as a one time thing and you are medically fine.
we were onloading nitrogen once, the truck pumped too hard and popped a tank relief... a few people passed out in a room about 200 feet away, the ambulance was called, all kinds of tests. turns out it was a i guess you could call it nitrogen surge, a cloud of it wafted thru, they got a wiff, passed out, and fortunately it passed and they were fine, and of course there are NO SYMPTONG NO LINGERING fingers pointing to it !!
Are they going to lose their license because although it is suspect, there is not conclusive evidence that is what did it? what if they pass out again? that's horse crap., id sue that doctor.
Huff a whippet, same thing happens, a minute later you are dine.... shrug.....
The fact that they did NOT find anything, and it has not happened again should be proof enough you are probably fine.
F that doctor going behind your back like that, ... stuff like that can get people waiting for you in a parking lot
Aaron