Q. I just found out my 8-month-old has a heart murmur, and I'm worried. Is it serious?
A. Probably not. The term "murmur" means an extra sound in the heart, which is caused when blood flows through the valves of the heart and around major blood vessels. The majority of these humming sounds, which are called "innocent murmurs," disappear as kids grow, usually by age 5. If your baby has such a murmur, it doesn't mean that anything is wrong with his heart. There's no reason to limit his physical activity as he grows or to treat him any differently than you would otherwise.
Once in a while, a murmur reveals a structural problem, such as a narrowed valve or a hole between chambers in the heart. In that case, the defect -- which is called a "pathologic murmur" -- can be surgically corrected if necessary.
If your baby is basically well, his doctor will follow the murmur on scheduled exams, then do more tests, such as an electrocardiogram (EKG) or an ultrasound if the sound changes. If there's still a concern or she thinks your child will need surgery, she'll likely refer you to a pediatric cardiologist for further evaluation.