Hi BC,
So sorry to hear about this. Regarding the visa medical, I'm afraid I can't help much with that but I wish you all the best with it.
I have however found some information which may be of help to you regarding travelling, see the link below
http://www.heartstroketayside.scot.nhs.uk/default.aspx?navigationid=355
Best case scenario, your tests will come back negative and you will be able to get on with you plans. Please try and stay calm in the mean time, look after your health before all else, we only get one body.
Good luck, I really, really hope all goes well for you.
Metoo x