Learning that you have or your child has a heart murmur can be scary. However, heart murmurs are quite common and often are harmless.

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In particular, they occur in many healthy children, who may or may not outgrow them as adults. They may also occur during pregnancy. Such murmurs are called "innocent" heart murmurs. They are not associated with medical or heart conditions, and do not require treatment or lifestyle changes.

Though many murmurs are innocent, some may indicate serious heart problems. For instance, heart murmurs may be caused by blood flowing through a heart valve made leaky or narrow by disease. Murmurs can also be caused by increased blood flow across a valve as a result of medical conditions such as anemia or hypothyroidism. Congenital cardiac defects (heart problems present at birth) can also cause heart murmurs. These often can be repaired with surgery.

Within the heart there are four chambers separated from each other by valves, or flaps, that regulate how much blood enters each chamber at any time. Healthy valves also help prevent blood from flowing in the wrong direction in your heart.

A healthy heart makes a "lub-dub" sound as it beats. The "lub" (systolic sound) happens when part of the heart contracts and the mitral and tricuspid valves close, and the "dub" (diastolic sound) occurs when part of the heart relaxes and the aortic and pulmonic valves close. A heart murmur is an extra sound, such as a whooshing, in the heartbeat caused by irregular blood flow through the heart valves.

Heart murmurs can be heard through a stethoscope and often are detected during routine physical examinations. On further examination, your doctor may find that the heart murmur is innocent. If your heart murmur is related to more serious heart problems, your doctor may refer you to a cardiologist (heart specialist). Medication or surgery may be recommended to treat the underlying problem. He or she may also suggest that you take extra precautions against getting a heart infection, such as by taking antibiotics when you have dental work or some surgeries. With thorough examination and proper tests, your doctor should be able to tell what causes your heart murmur.

Symptoms
Many people with heart murmurs experience no symptoms. However, some murmurs can occur in conjunction with these other symptoms:

• Chest pain
• Rapid heartbeat (palpitations)
• Breathlessness
• Fatigue
• Bluish skin color or fingertips (sometimes seen in babies with congenital heart defects)

November 2000, Reviewers: the Cleveland Clinic

Heart Center | Introduction & Symptoms | Causes & Treatments | Illustration