A heart murmur is simply an extra sound heard when listening to the heart. The normal sounds a heart makes are from the valves closing. If there is turbulence, or disturbance, in the flow of blood through the heart or major blood vessels around the heart, a murmur may be heard.
Heart murmurs can generally be divided into two categories:
Murmurs that are not due to structural problems in the heart also called "innocent murmurs" or "functional murmurs". Innocent murmurs are very common. Some pediatric cardiologists estimate a heart murmur can be heard in 90 percent of children with anatomically normal hearts between the ages of 4-7 years. These murmurs do not usually require multiple follow-up visits with a cardiologist.
Murmurs which are due to a structural problem of the heart (such as a hole in the heart, a narrowed heart valve or a leaky heart valve). These murmurs require further evaluation and follow-up with a cardiologist.
Most murmurs can be categorized into one of the above two categories with a careful evaluation by a pediatric cardiologist. The physician will ask a number of questions about your child's growth, development, frequency of illnesses, and family history of heart disease. The physician will then perform a thorough examination of your child, including careful listening to the heart with a stethoscope. Usually the pediatric cardiologist will obtain an electrocardiogram (test that records the heart's electrical activity -- also called an ECG or EKG) as part of the evaluation of a heart murmur.
There are many characteristic sounds the heart can generate which will almost always allow characterization of a murmur as "innocent" or not. Occasionally, it can be difficult to characterize a heart murmur on the basis of a physical examination and electrocardiogram. In these cases, an ultrasound of the heart, called an echocardiogram, may be performed to look at the structure of the heart in detail.
Generally, a child with an innocent heart murmur will be discharged from further cardiology follow up. Innocent heart murmurs do not make the child more likely to have heart attacks or high blood pressure later in life. Your child's physical activities should not be restricted because of the heart murmur. The best way to ensure a healthy heart in the adult years is to develop good exercise and eating habits as a child.
Even if your child has been diagnosed with a heart murmur that is due to a structural problem of the heart, this does not necessarily mean that your child will require heart surgery. Some murmurs are due to small holes between the two lower chambers of the heart. These holes do not get bigger and often close by themselves. Other murmurs are due to narrowing or leaking of one of the valves of the heart, however this may be mild. Many children with structural heart disease lead normal active lives, get married, and have children.
People who have structural disease of the heart (such as a hole in the heart or an abnormal heart valve) are at higher risk for developing an infection of the heart (endocarditis) following routine teeth cleaning and other dental procedures such as fillings. Endocarditis can also develop following invasive medical procedures (for example, procedures that use a lighted scope to examine the stomach, colon or bladder). Taking appropriate antibiotics as directed by your doctor or dentist at the time of these procedures can prevent endocarditis. If your child requires antibiotics for such procedures because of a heart condition, your pediatric cardiologist will give you a card that specifically lists the type of antibiotics and dose schedule required. It is very important that these recommendations be followed, as endocarditis is a serious infection that can be fatal.