Heart MurmursI think it depends on the degree of the murmur. I have a 7 year old GSP with a murmur that was diagnosed at 3 years of age. I was told that he would need tests to determine the extent of the problem and that he would need to be on medication for the rest of his life. We opted for neither. He is an extremely active dog and lives his life at a hectic pace. We couldn't slow him down even if we wanted too :-) Yes, he does cough on waking and sometimes if he has really been acting like a loony which is most of the time :rolleyes: I tend to keep his weight in check and keep him fit and so far so good. I was worried that he would have a heart attack but my vet assured me that a heart murmur in dogs is not the same as in humans. He did tell me that my dog would not make old bones, but he is now 7 and still going strong. If your vets can't agree if your dog has one or not then I would hazard a guess that it can not be that severe. I know it is a shock being told that your dog has a heart murmur, but in my case, it has made no difference to my dog at all. He has a great life and it hasn't stopped him from enjoying it :-)
Personally, I would not breed from an animal with this defect.
Good Luck with your dog.