Sly was diagnosed by our locum vet as having a heart murmur last year, she didn't "grade" it for me, either, so I worried all year. But when I took him for his MOT and vaccs last week the regular vet couldn't hear anything wrong.
Apparently the stress of being at the vet can make the murmur sound more pronounced, and Sly was completely terrified the first time, but much more relaxed this year, so although my vet can't rule out his colleague's earlier diagnosis, he has told us not to worry at all because if it is there it is very mild indeed.
He told us to look out for signs of exhaustion when he's playing, and calm him down if he starts panting hard, other than this there's nothing we can do except enjoy our mischievous little scamp.
The only consideration he mentioned would be getting insurance, the murmur would need to be declared as a pre-existing condition and problems associated with his heart would not therefore be included.
Did your vet tell you more?
Glad the dental went well