Heart Murmurs in Children
Basics of Heart Murmurs
A heart murmur is an extra or unusual sound heard during a heartbeat that is made by blood circulating through the heart's chambers or valves, or through blood vessels near the heart. Murmurs can range from very faint to very loud and sometimes make a whooshing or swishing noise. The two major categories of murmurs are innocent (harmless) and abnormal. But a child’s physician may use other words to describe a child’s heart murmur, including:
- Systolic murmur. A heart murmur that occurs during a heart muscle contraction. Systolic murmurs are divided into ejection murmurs (often due to blood flow through a narrowed vessel or irregular valve) and regurgitant murmurs (typically due to mitral or tricuspid regurgitation, when the blood leaks back into the atria from the ventricles).
- Diastolic murmur. A heart murmur that occurs during heart muscle relaxation between beats. Diastolic murmurs are due to a narrowing (stenosis) of the mitral or tricuspid valves, or regurgitation of the aortic or pulmonary valves.
- Continuous murmur. A heart murmur that occurs throughout the cardiac cycle.
Causes of Heart Murmurs
Why some children have innocent heart murmurs while others do not remains unknown. However, research has identified various causes of abnormal heart murmurs, which include:
- Defective heart valves
- Holes in the interior heart walls (atrial septal defect or ventricular septal defect)
- Congenital (present at birth) heart defects
- Anemia (a decrease in the red blood cells)
Symptoms of Heart Murmurs
Children with innocent (harmless) heart murmurs don’t have any signs or symptoms other than the murmur itself because this type of murmur is not caused by heart problems.
Murmurs related to a congenital (present at birth) heart defect or other structural heart problem are heard loudest in the area of the chest where the problem occurs. Some large defects have almost no murmur in the newborn due to normally elevated pressures in the lungs’ blood vessels. Murmurs may be inconsistent and difficult to hear in an infant who is agitated or crying. Thus, murmurs may be missed or undetected.
Health Problems Associated with Heart Murmurs
Innocent murmurs usually resolve by the time a child reaches adulthood. If a child's health care provider hears an innocent murmur, he or she may perform additional tests to rule out a heart defect. A child with an innocent murmur can live a normal life and be as active as any other healthy child.
Treatment for Heart Murmurs
If a child has an abnormal heart murmur, a physician will recommend treatment for the condition or disease causing the murmur.