Although not normal, it is very common for newborns to be born with a heart murmur–a small hole or tear in the tissue of the heart. It sounds scary but usually it is nothing to worry about. A doctor will pick it up on the first day or two, and then they will send you home as long as the baby passes an echocardiogram (ECG) and doesn’t show any other symptoms (i.e. especially breathing difficulty). They then tell you to make an appointment with your pediatrician (like you do for all newborns) and see if he/she still hears it. This gives the baby’s heart a couple days to heal on its own, which sometimes it does.
If the pediatrician still hears the murmur, he/she will probably refer you to a children’s cardiologist and the cardiologist will do another ECG and listen to the murmur. A cardiologist’s ear is so fine-tuned for diagnosing murmurs from a simple stethoscope that it is amazing. He or she will usually be able to tell you how big the murmur is and in what part of the heart, just by listening for a couple seconds.
Apparently the region of the heart is important because there is a greater percentage of the murmur healing depending on which chamber it is in. I can’t remember the facts anymore, but the chamber that my baby’s murmur was in had a 75% chance of healing all by itself in a couple months. I believe there is only one chamber where it normally doesn’t heal on its own. Usually the cardiologist will send you away to return in another two months, just for a listen and another ECG. The vast majority of murmurs heal on their own by that time because the baby is growing so much during that first two-month period.
If for some reason your baby’s heart murmur doesn’t go away by then, it can still go away any time during the first five years of its life. The pediatrician will keep an eye (ear) on it as they grow. But if for some reason it still doesn’t go away, usually the consequences are minor. The child has to go on antibiotics for dental procedures, and other medical or surgical procedures might be more complicated because there is a risk of infection that can travel to the heart. But there is usually not any other trouble, including in the area of exertion. Things should be normal.
It is important to know that while a heart murmur is considered “a heart condition,” you don’t need to panic. The only time that panic is warranted is if the baby starts having trouble breathing… chest heaving, sucking in at the breastbone, bluish face, clammy or non-circulating extremities. This is because the heart circulation directly affects the respiratory system. You’d probably notice very soon if this were to happen post-partum. Take the baby to the ER immediately.