Hi G.,
I have a heart murmur (mitral valve prolapse) that I have known about since I was about 12. My mother has it and her mother had it, and it hasn't affected either of them as far as I can tell. I beleive that the specialist will just do an echocardiogram to make sure that there isn't some kind of major defect, and simply to check that it is indeed only MVP. Mitral valve prolapse (MVP) is the chief cause of a heart murmur and simply means that when the mitral valve pumps blood out of the heart, a teeny bit of it flows back into the heart. The noise made by this is often detectable and therefore it is commonly referred to as a heart murmur.
I have never even noticed anything, and the only reason I was even aware of it is because my grandmother was diagnosed prior to a mastectomy. Since MVP is genetic, my mother and I were both tested. I lettered in 4 sports in high school, and I still run about 40 miles a week, so it has certainly never physically affected me. I used to have to take antibiotics when I went to the dentist, but even that isn't recommended anymore. So, short of having major surgery, you never notice it. When you have surgery (or when I delivered my kids) you have to have an antibiotic drip because there's some kind of risk of infection that people with MVP have that others do not. NO BIG DEAL... you're right! Good luck holding them still for the echocardiogram, but you can tell them all about your pregnancy ultrasound when they do it (which they'll think is cool, I'm sure!).