Heart Murmur (Systolic Murmur)

What is a heart murmur?

Blood normally flows smoothly into and out of the heart. However sometimes there may be a structural abnormality in the heart, such as a "hole in the heart", which can lead to the blood flow being turbulent. This turbulent blood flow creates an abnormal sound that can be heard with a stethoscope (an instrument used to listen to sounds within the body).

A heart murmur is also known as a systolic murmur.

What causes the murmur?

A heart murmur can be caused by a number of things. Examples include:

  • A heart valve abnormality: A heart has four valves which help control the flow of blood. Sometimes a valve develops an abnormality, such as stenosis (the valve narrows, interfering with the outflow of blood). Many heart valve abnormalities are caused by rheumatic fever, an illness that can develop from an untreated strep throat infection.
  • Endocarditis: This is an inflammation and infection of the heart valves and endocardium (the inner lining of the heart chambers).
  • Congenital Heart Problems: A congenital condition is one which is present from birth. For example, a 'hole in the heart' (septal defect). A 'hole in the heart' is an abnormal opening in the septum (the wall which divides the left-hand-side of the heart from the right).

Does a murmur always indicate that something is wrong with the heart?

No. Some people have 'innocent' murmurs. These can be produced by a normal heart. Therefore a murmur does not always mean that there is something wrong with the structure of the heart. For example, you may have a murmur if your blood moves quickly.

What are the symptoms of a heart murmur?

An "innocent" murmur will usually present no heart-related symptoms. With other murmurs, symptoms can depend on the underlying cause.

If a murmur is interfering with the heart's ability to pump blood, a person may experience a rapid heartbeat, shortness of breath, chest pain, or feelings of lightheadedness.

Many murmurs are discovered by accident during routine exams.

How long do heart murmurs last?

Innocent murmurs can lessen over time and in some cases disappear altogether.

If the murmur is related to a heart problem, its duration can depend on the underlying cause. For example, if a person has a congenital heart defect (a condition present since birth), the murmur may be present for the person's whole life. In some cases, the murmur may worsen over time.

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