Don't worry too much dude. I was told the same thing on my second interview. Damn near scared the hell out of me. Not so much for thinking that I wasn't gonna get Cathay, but the docotor made it sound like my flying carreer might be over! (at least that is what I heard).
I went on to get the further tests they required before giving a decission to me, and 2 weeks later they hired me. Go figure.
If anything, you can seek comfort in knowing that they want to hire you. Otherwise, IMHO, I think they wouldn't even bother asking you for further medical tests.
So don't sweat it too much. But If you do, I know how that feels and I feel for you.
