A heart murmur in a child refers to an extra sound heard during a heartbeat. These sounds are a frequent finding in children, and in most instances, they are harmless. They often represent the sound of blood moving normally through a healthy heart.
What is a Heart Murmur?
A heart murmur is the sound produced by turbulent blood flow through the heart’s chambers, valves, or nearby blood vessels. The heart normally makes two distinct sounds, “lub-dub,” from the closing of heart valves. A murmur is an additional whooshing, swishing, or blowing sound heard between these normal beats.
Doctors detect these sounds using a stethoscope. A murmur is not a disease in itself; it indicates that blood flow is not entirely smooth.
Types of Heart Murmurs in Children
Heart murmurs in children fall into two main categories: innocent and abnormal. Innocent murmurs are very common, occurring in up to 80% of children.
Innocent murmurs, also known as functional or physiologic murmurs, are harmless sounds caused by blood flowing rapidly through a structurally normal heart. They do not indicate any heart defect or disease. These murmurs are often louder when a child has a fever, is excited, or during periods of rapid growth. Innocent murmurs typically do not require treatment and frequently disappear as a child grows.
In contrast, abnormal, or pathological, murmurs are less common and signify an underlying heart problem. These murmurs can be louder and may have a harsh quality. They warrant further medical evaluation to identify the specific cause, as they suggest a structural issue within the heart.
Causes of Abnormal Heart Murmurs
Abnormal heart murmurs in children are caused by structural problems within the heart or certain acquired heart conditions. Many issues are present at birth, known as congenital heart defects. Examples include holes in the heart walls, such as ventricular septal defects (VSD) or atrial septal defects (ASD), which allow blood to flow abnormally between chambers.
Other congenital issues involve problems with heart valves, such as narrowing (stenosis) or leakage (regurgitation), which can disrupt smooth blood flow. Conditions like coarctation of the aorta (a narrowed artery) or patent ductus arteriosus (PDA), where a blood vessel fails to close after birth, can also cause abnormal murmurs.
Less commonly, abnormal murmurs can arise from acquired heart conditions that develop after birth. These include infections affecting heart valves, such as endocarditis, or inflammatory conditions like rheumatic fever. Conditions that alter blood flow, like severe anemia or an overactive thyroid gland, can also result in murmurs that resolve once the underlying condition is treated.
Diagnosis and Management
A heart murmur is typically first detected by a pediatrician during a routine physical examination. The doctor listens to the heart’s sounds, noting characteristics like loudness, pitch, timing within the heartbeat, and location on the chest. If an abnormal murmur is suspected, the child is often referred to a pediatric cardiologist.
The pediatric cardiologist will perform a thorough evaluation, including diagnostic tests. An echocardiogram, an ultrasound of the heart, provides detailed images of its structure and blood flow. An electrocardiogram (ECG or EKG), measuring the heart’s electrical activity, and a chest X-ray may also be performed.
For children with an innocent heart murmur, no treatment is needed, and they can participate in all normal activities. If an abnormal murmur is diagnosed, management depends on the underlying cause. This can range from monitoring and medication to procedures or surgical intervention. Many heart conditions in children are treatable.