u/Few-Conversation5250

I picked up my pup last saturday and today (Follwing Thursday) I took him to the vet for his 9 week shots. My vet found a grade 3-4 heart murmur, possibly needing surgery. We’re now looking at being referred out to have it looked further into, and possibly looking a surgery t. His breeder took him for his 6 weeks shots. Is this something that would/should have been noticed at his 6 week visit? Should I message the breeder? It’s only been less than a week and we’ve fallen so in love with our pup and want to do what’s best for him. I just don’t know how to feel about if this was something that we should’ve been made aware of beforehand.