Hi!! I have two bullies with heart problems and the older one is almost 15 months old and still going strong, Remy is the youngest one at almost 5 months and he is the most active puppy I've seen! They were both diagnosed at around 8 weeks with what could just be a murmur but turned out to be a grade 3. Did your vet give your puppy a number on the murmur, because that will explain somewhat on how serious it is. Both Sebastian and Remy's turned out to be Pulmonic Stenosis, Sebastian's is severe while Remy is moderate. How old is your puppy now? Because if he/she is younger than 4 months, I would recommend just waiting because by 16 weeks most puppies will have outgrown innocent murmurs. If the vet still hears it after that they will likely recommend getting an echo done. For right now, enjoy your little bundle of bullyness and give him/her a happy puppy life. I am always here though for any support or more answers for you if you have additional questions, which I'm sure, you will have!