A heart murmur is a continuous sound that is audible with a common stethoscope, produced when blood passes through particular areas of the heart. The heart has four chambers, two atria (singular = atrium) and two ventricles separated by a “skeleton” of cartilage that separates each chamber.
This skeleton is made up of the atrial septum, the ventricular septum, and four valves (aortic, pulmonary, mitral, and tricuspid) that direct blood flow in a specific route within the heart allowing the most efficient use of each heartbeat to pump blood to the rest of the body.
Normal heart sounds
The doctor listens to your heart at different places on your chest to hear the sounds your heart valves make as blood travels through your heart. Normally, the heart beat has two sounds – lub-dub.
The first sound is heard as the mitral and tricuspid valves close. The second heart sound is the aortic and pulmonic valves snapping shut.
What are the risk factors for heart murmur?
A heart murmur is a physical finding of an underlying heart condition and in many instances may be of no consequence. The risk factor for developing a particular murmur is the risk factor for the underlying condition.
Congenital heart disease tends to have a familial basis, meaning that there may be a genetic predisposition for a baby to develop a structurally abnormal heart.
Some valvular diseases are present at birth, but take a lifetime to develop symptoms. For example, the aortic valve is supposed to have three leaflets that come together; some people are born with a valve that has only two leaflets (bicuspid). Over time, a two-leafed valve may be more prone to calcification and narrowing.
Symptoms may only be seen later in life.
Some valve diseases are due to infection and past rheumatic fever with heart valve inflammation due to a bacterial streptococcus infection.
With present day screening for strep infections and the appropriate use of antibiotics, this risk factor has decreased significantly.
Other risk factors for heart valve abnormalities include atherosclerotic heart disease, heart attack, aortic aneurysm, and connective tissue disorders such as systemic lupus erythematosus and Marfan syndrome.
Each condition affects the valves in a different way causing them to malfunction and develop the physical finding of a heart murmur.
A heart murmur in itself causes no symptoms and it generally cannot be heard by the person affected. It is the underlying structural issue of the heart that may cause problems. Note that many heart murmurs are of no consequence.
Congenital heart disease may present with newborns who have difficulty breathing and who are cyanotic, meaning that the heart cannot circulate blood and oxygen from the lungs to the body. S
ome infants with heart issues may have difficulty feeding, developing, and growing appropriately.
Most heart murmurs in well-developed children are harmless.
In adults, heart abnormalities may cause chest pain, shortness of breath, and swelling of the extremities among many other symptoms.
Palpitations or a sensation of an irregular heartbeat are occasionally seen in patients with heart valve abnormalities.
Causes of heart murmurs
Valvular heart disease is the most common cause of a heart murmur
- Valve stenosis – a narrow, tight, stiff valve, limiting forward flow of blood.
- Valve regurgitation – a valve that does not close completely, allowing backward flow (a “leaky” valve)
- The abnormal changes to the valve cause the abnormal heart sound (murmur).
Other causes of heart murmurs include:
- Hypertrophic cardiomyopathy
- Septal defect
Functional causes for heart murmurs
Murmurs can be caused by increased blood flow across the valve related to other medical conditions without valvular heart disease, such as:
Murmurs can be present without any medical or heart conditions. Two common examples include:
- Childhood murmurs
Important information about heart murmurs
It is important to have regular physical exams to detect any abnormal heart sounds. If a murmur is heard, further evaluation will be required to determine why the murmur is present, which valve is involved, and the severity of the problem.
If the murmur is due to a heart valve problem:
- Follow-up with a cardiologist will be required to evaluate the progression of the valve disease.
- Most people who have a heart murmur require measures to prevent valve infection. These include:
- Tell all your doctors and dentist you have valve disease
- Call your doctor if you have symptoms of an infection
- Take good care of your teeth and gums
- Take antibiotics before you undergo any procedure that may cause bleeding
- A wallet card may be obtained from the American Heart Association with specific antibiotic guidelines. Call your local American Heart Association office or nationally
When should I seek medical care for a heart murmur?
A heart murmur generally does not cause any symptoms. It is the underlying heart function issues that often cause patients to seek medical help.
Chest pain and shortness of breath should always be taken seriously and not ignored. Medical help should be accessed immediately if a person has heart or lung concerns.
How is a heart murmur diagnosed?
A heart murmur is usually diagnosed during a physical examination by the health care practitioner while he or she listens to heart sounds with a stethoscope.
What is the treatment for a heart murmur?
The treatment for heart murmur depends upon the particular cause and the underlying medical status of the patient. Many murmurs need no further evaluation, can be monitored, or are a normal variant. Some murmurs are associated with serious infected valves and require antibiotics.
Some valves are structurally damaged and require surgical repair.
What are the complications of a heart murmur?
A heart murmur is the physical finding of an underlying structural issue within the heart. A heart murmur itself has no complications. The ramifications of a heart murmur are based on the particular underlying abnormality causing the murmur, and the effect it has on cardiac physiology.
Can heart murmur be prevented?
It is important to remember that a heart murmur is a physical finding and is not a disease or structural heart problem. Rather it is the sound that is made because of a potential blood flow problem within the heart.
Maintaining a life-long heart-healthy lifestyle may help prevent some heart valve issues.
These lifestyle opportunities include keeping blood pressure, cholesterol, and diabetes under control. It is a positive choice not to smoke. Regular exercise and weight management also contribute to a healthy heart.
Historically, rheumatic fever was a complication of strep throat (streptococcal pharyngitis). This could cause heart valve damage and the development of a heart murmur.
With the advent of good screening tests for strep infections and the appropriate use of antibiotics, rheumatic fever is a rarely diagnosed condition.