Heart Murmurs in Children

What is a heart murmur?

Murmurs are extra or unusual sounds made by blood circulating through the heart's chambers or valves, or through blood vessels near the heart.

What causes a heart murmur?

Heart murmurs may be heard in a normal healthy heart of a child, or they may be caused by a number of factors or diseases, including:

• Defective heart valves

• Holes in the walls inside the heart (atrial septal defect or ventricular septal defect)

• Other structural heart defects (congenital or present at birth) 

• Fever

• Anemia (low blood counts)

What are the different types of murmurs?

Your child's health care provider will evaluate a murmur based on several factors. Murmurs are analyzed for pitch, loudness, location, and duration. They also are graded according to their intensity (on a scale of 1 to 6, with 1 being very faint and 6 being very loud).

Types of murmurs include the following:

• Systolic murmur. A heart murmur that occurs during a heart muscle contraction or when blood is pushed out to the body.

• Diastolic murmur. A heart murmur that occurs during heart muscle relaxation between beats or when heart chambers are re-filling before the next contraction.

• Continuous murmur. A heart murmur that occurs throughout the cardiac cycle, during contraction and relaxation

Heart murmurs can change and be heard or not heard at different times. Some large heart defects have almost no murmur in the newborn due to unequal pressures on both sides of the heart. Murmurs may be inconsistent and difficult to hear in an infant who is agitated or crying. Thus, sometimes murmurs may be missed or not detected. For these reasons, your doctor will listen and evaluate your child's heart sounds multiple times throughout your child's growth and development.  

Do all murmurs signify heart disease?

Not all heart murmurs mean heart disease. Sometimes, a murmur may be heard in a normal child as the strong, healthy heart pumps blood into the vessels. This is known as an "innocent murmur." It usually resolves as the child grows. 

Murmurs can also be heard in a child with no heart disease but who has a fever or who is anemic; these murmurs often go away when the underlying problem is treated.

What tests may be used to evaluate a heart murmur?

• Chest X-ray. This helps evaluate the size of the heart. 

• Echocardiography (echo). An ultrasound procedure that evaluates the structure and function of the heart. An ultrasound generates pictures using sound waves.

• Electrocardiogram (ECG). A simple test using stickers placed on the chest that can detect and record the electrical activity of the heart.      

What is the treatment for a heart murmur?

Many heart murmurs are normal, extra sounds in children with strong, healthy hearts. These children require no treatment. Some of these heart murmurs may resolve over time. Even if there is a hole or structural defect found in the heart, it may close as your child grows. However, some defects will require surgery to correct. Others are caused by conditions not related to the heart, such as anemia. In these cases, the heart murmur will lessen or resolve as the underlying is treated.