While many greys can have a murmur but no heart disease, my Pearl DID have heart disease diagnosed at age 5, then hypertension diagnosed at age 6. We had regular appointments with her cardiologist for the rest of her life. And while there were changes with the heart as she got older, cancer took her at age 12.
I'm lucky, she was insured before the diagnosis and was covered for most of it.
An echo will tell you if it's something to be concerned about or not.