Normal heart sounds come in pairs. The sounds are often described as a constant “lub-dub, lub-dub.” The first “lub-dub” is the sound of the mitral and tricuspid valves closing. The second “lub-dub” is the sound of the aortic and pulmonary valves closing soon after. But if there is a problem, a murmur may be added to this normal “lub-dub.” By using a stethoscope to listen to your heart, your doctor’s trained ear can tell if the abnormal sound indicates turbulence. This is called a heart murmur.
Some heart murmurs are a harmless type called innocent heart murmurs. They are common in children and do not require treatment or lifestyle changes. In most cases, innocent murmurs disappear when children reach adulthood.
While some heart murmurs are innocent, others are a sign of a more serious heart problem. In these cases, the sound may indicate that blood is flowing through a damaged or overworked heart valve, that there may be a hole in one of the heart’s walls, or that there is a narrowing in one of the heart’s vessels.
What causes a heart murmur?
Murmurs can occur when blood is forced to flow through a narrowed valve (called stenosis), or when it leaks back through a defective valve (called regurgitation). These valve problems may be present at birth (congenital) or develop later in life because of rheumatic fever, coronary artery disease, infective endocarditis, or aging.
In other cases, a heart defect, such as a hole in one of the heart’s walls, can cause a murmur. Conditions such as pregnancy, anemia, high blood pressure, fever, or an overactive thyroid gland may also cause a heart murmur that comes and goes.
What are the symptoms?
Most people with a heart murmur do not have symptoms. Usually the murmur is found during a physical exam for other symptoms, such as chest pain, shortness of breath, fatigue, or the presence of a blue coloring to the skin or fingertips (called cyanosis).
How are heart murmurs diagnosed?
In most cases, your doctor will be able to hear your heart murmur by using a stethoscope to listen to your heart (a technique called cardiac auscultation). Heart murmurs change as your body position or breathing changes, so you may be asked to stand up, squat, lie down, breathe deeply, or hold your breath while the doctor listens to your heart.
To find out if your heart murmur is innocent or if it is caused by another heart problem, your doctor may also order these tests:
- A chest x-ray to see if your heart is enlarged.
- Electrocardiography (ECG or EKG) to check for an irregular heartbeat (arrhythmia) or an enlarged heart.
- Echocardiography to see valve function, heart wall motion, and overall heart size.
- A special medicine called amyl nitrate that is used to define certain heart murmurs. Your doctor will have you breathe in the medicine, which briefly changes your blood pressure and heart rate.
How are heart murmurs treated?
The treatment for a heart murmur depends on the cause. Innocent heart murmurs usually do not need to be treated. If your heart murmur is caused by an underlying condition, such as high blood pressure, your doctor will treat that condition. If your heart murmur is caused by disease of the valve itself (intrinsic valve disease) or other heart defects, medicines or surgery may be needed.
Doctors used to give anyone with a heart murmur antibiotic medicines before a dental or surgical procedure to prevent infection in your heart valves. (Some of these procedures may cause bacteria to enter the bloodstream, which can lead to infection.) Today, most doctors do not recommend routine antibiotics unless the murmur is caused by intrinsic valve disease. Talk to your doctor or dentist for current guidelines.
Your doctor may prescribe certain medicines, depending on the underlying cause of your heart murmur.
- Blood thinners (anticoagulants), which can prevent blood clots from forming and blocking blood vessels.
- Beta-blockers, which help to slow a rapid heart beat or fluttering.
- Medicines that lower blood pressure (antihypertensives), which ease the workload on the heart.
- Antiarrhythmics, which control an irregular heartbeat (arrhythmia) and relieve the symptoms of heart palpitations.
- Diuretics, which lower your blood pressure by ridding your body of extra fluid and salt.
- Digoxin, which strengthens the force of the heartbeat.
In some patients, surgery may be needed to repair a heart defect or repair or replace a damaged heart valve.