Heart Murmur

What is a heart murmur?

A heart murmur is an abnormal audible “swooshing” of blood across a heart valve. The heart has four valves which control blood flow between the four chambers of the heart. Normally, when the valve is closed, no blood can get through. When the valve opens, blood flows through without obstruction. If the valve doesn’t open or close completely, though, blood can seep through. Blood moving through a partially-closed heart valve creates a whooshing sound between heartbeats. Heart murmur sounds are typically detected by healthcare providers who are listening to the heart with a stethoscope.

A heart, or cardiac murmur can occur in people of all ages. A murmur may be harmless; murmurs that do not cause problems are called innocent murmurs. Innocent heart murmurs commonly occur during pregnancy and activities that promote an increase in blood flow. Common innocent murmurs in children include Still’s murmur, pulmonic murmur, and venous hum. However, some abnormal heart sounds and murmurs indicate a problem, such as congenital heart disease (heart disease due to heart problem present at birth).

Your risk of a heart murmur is higher if you were born with a heart defect or have a family history of heart defects. Medical conditions that affect the heart and blood vessels—such a high blood pressure and infection of the heart—also increase the risk of heart murmur.

Most people with heart murmurs have no outward signs or symptoms. If a doctor hears abnormal heart sounds and suspects a problem, cardiac diagnostic and imaging tests, such as an echocardiogram, can help determine the underlying cause and if treatment is necessary. For some heart murmur causes, treatment is necessary to prevent such complications as arrhythmia or heart failure.

Rarely, heart murmurs can interrupt the flow of blood and oxygen through the body and cause such symptoms as shortness of breath, dizziness, and enlarged neck veins. Seek immediate medical care—call 911—if someone you are with passes out or cannot get enough air.

What are the symptoms of a heart murmur?

Innocent heart murmurs usually do not cause any symptoms. Often, a doctor or nurse notices a heart murmur during a routine physical exam. Even heart murmurs that result from a problem with the heart or heart valves may not cause symptoms. When symptoms do occur, they require prompt medical care. If your child’s pediatrician hears a heart murmur, he or she may refer you to a pediatric cardiologist for follow-up care.

Seek emergency medical care (call 911) for symptoms that could indicate a serious problem with the heart or heart valves including:

• Persistent cough

• Shortness of breath

• Blue-tinged fingertips or lips

• Enlarged neck veins

• Heavy sweating with minimal exertion

• Dizziness

• Fainting

Heart murmurs in babies may be accompanied by these serious symptoms:

• Rapid breathing

• Bluish tint to skin and fingernails

• Tiring easily, even while nursing

• Little to no weight gain compared to infants of same age and gender

Seek prompt medical care (or call 911) if you notice rapid breathing or a bluish tint in your child.

What causes a heart murmur?

The sound of a heart murmur is caused by the abnormal flow of blood across a heart valve. Possible causes of heart murmurs include:

• Congenital heart abnormalities including atrial septal defect, patent ductus arteriosus (cardiac shunt), and valve defects

• Endocarditis, which is an infection of the heart

• Rheumatic fever, which is a complication of untreated streptococcus bacterial infection such as strep throat

• Stiffening and narrowing of the heart valves such as aortic valve stenosis

Innocent heart murmurs in children and adults can be caused by anything that temporarily increases blood flow through the valves including:

• Anemia

• Exercise

• Fever

• Growth spurts

• Hyperthyroidism

• Pregnancy

What are the risk factors for heart murmur?

A number of factors increase the risk of developing a heart murmur, but not all people with risk factors will get a heart murmur. Risk factors for heart murmur include:

• Congenital heart defects

• Endocarditis

• Family history of heart defects

• High blood pressure

• History of rheumatic fever

How are heart murmurs treated?

Most heart murmurs do not require treatment. If the murmur affects your heart’s ability to deliver enough blood and oxygen to the rest of your body, treatment may be required to prevent complications, such as heart failure. Common treatments for heart murmur include:

• Medication. Because heart murmurs are associated with an increased risk of blood clots, healthcare providers may prescribe blood-thinning medication. Statins (medications that decrease the amount of cholesterol in the body), diuretics (medications that help the body eliminate excess fluid), and blood pressure medications may also be prescribed to people with heart murmurs, depending on the underlying cause of the murmur.

• Surgery. If medication cannot sufficiently treat your heart murmur symptoms, your doctor may suggest surgical intervention. Surgical treatments for heart murmur range from balloon valvuloplasty (the use of a tiny balloon to enlarge the valve opening) to valve replacement.

What are the potential complications of a heart murmur?

Complications of a heart murmur may include:

• Infection. Some people with heart murmurs may develop heart infections after dental work. Ask your doctor if you should take antibiotics prior to dental work or other medical procedures.

• Fainting. If the heart murmur restricts the flow of blood and oxygen, the affected person may faint. Treatment of the underlying cause of the heart murmur should prevent future fainting episodes.

• Arrhythmia. Some causes of heart murmur can lead to an abnormal heart rhythm.

• Heart failure. This can develop if the heart must work harder than normal to pump enough blood to the rest of the body.

Some heart murmurs disappear over time, as a result of growth or medical treatment.