Heart murmurs

What is a heart murmur?

A heart murmur is an additional sound that can be heard when listening to the heartbeat using a stethoscope. Typically, it sounds like a swishing, whooshing or rasping noise that occurs between the usual beats, or changes in the beats themselves.  

In many cases, heart murmurs are completely harmless and will go away on their own in time. This is called an ‘innocent’ heart murmur. However, some types of heart murmur can indicate an underlying health problem that should be monitored or requires treatment. This is called an abnormal heart murmur. 

Our adult and children’s heart specialists at Evelina London Children’s, Harefield and Royal Brompton hospitals are world-leaders in their field. We can provide a fast and accurate diagnosis for a heart murmur and provide the best treatment options, if needed.

What causes a heart murmur?

Heart murmurs are common in babies, children and adults.  

Most heart murmurs do not cause any significant issues. However, in some cases they are due to an underlying heart problem that requires treating. 

There are 3 main types of heart murmur. These are: 

• systolic murmur – this is when a murmur occurs when the heart is emptying as it pumps blood to the rest of the body 
• diastolic murmur – this murmur occurs when the heart relaxes between beats to fill up with blood 
• continuous murmur – this is when the murmur occurs throughout the heart cycle

Harmless (innocent heart murmurs)

Innocent heart murmurs occur in people with structurally normal hearts.  

They are more common in babies and children as they naturally have a faster heart rate than adults. As their blood has to negotiate several tight bends as it travels through the heart, this can mean that their heartbeat sounds abnormal.  

Innocent heart murmurs usually disappear as a child grows, as bends within the heart become less tight, and their heart grows and settles deeper in the chest. Sometimes, innocent heart murmurs can continue for life without causing any serious health problems.

Abnormal heart murmur

An abnormal heart murmur occurs when the extra sounds in the heartbeat are caused by a heart problem, such as a structural deformity within the heart or another issue that causes abnormal blood flow.  

For example, an abnormal heart murmur can occur due to narrowed, or leaking heart valves, or a hole between the two chambers of the heart. They are rare in babies and young people, unless they have a heart problem present at birth – called congenital heart disease.

What are the risk factors for a heart murmur?

There are a number of risk factors that could increase the likelihood of having a heart murmur. These include: 

• a family history of congenital heart disease 
• an overactive thyroid (hyperthyroidism) 
• anaemia (low red blood cell count)  
• heart valve disease 
• hypertension (high blood pressure) 
• hypertrophic cardiomyopathy 
• pregnancy (as the body makes and pumps more blood for a baby)

If you feel that you or your child are at risk of a heart murmur and would like to speak to one of our consultants, contact our team to arrange an appointment.

Heart murmur symptoms

Most heart murmurs cause no symptoms and are only discovered during a routine medical exam.  

However, depending on the heart condition causing the murmur, you or your child may experience: 

• a continuous cough that won’t go away 
• chest pain 
• dizziness 
• fainting 
• heart palpitations 
• lack of appetite 
• poor growth 
• shortness of breath 
• sweating a lot when resting or doing minimal physical activity 
• swelling in the arms, legs or abdomen

If you are concerned about any of the symptoms listed above, book an appointment with one of our heart specialists who can help with a fast and accurate diagnosis.

Heart murmur diagnosis

The majority of heart murmurs are first detected by a doctor listening to your heart through a stethoscope. Heart murmurs are graded from 1 to 6 based on the strength of the sound they cause. Grade 1 is a very low-grade murmur, while 6 is the highest.  

In some cases, our cardiologists may recommend a test called an echocardiogram. This is a specific type of ultrasound that can be used to visualise the heart and assess blood flow in real time.  

Other heart tests which may be recommended include a chest X-ray to see if the heart muscle is bigger than it should be and/or an electrocardiogram (ECG) which is a test to measure the level of electrical activity in your heart.  

Once a diagnosis of a heart murmur has been confirmed, our cardiologists will talk to you about whether treatment will be required.  

If you are looking for a fast and accurate diagnosis for a heart murmur, get in touch with our helpful customer service team who can book an appointment with one of our consultants.

Treatment for heart murmurs  

Innocent heart murmurs usually don’t require treatment. However, our cardiologists will recommend regular monitoring and that your GP, or your child’s GP, is informed of the condition. Innocent heart murmurs will likely disappear with time. 

If an abnormal heart murmur is confirmed, our cardiologists will recommend a treatment that depends on the type and severity of the heart murmur. This could involve medications, or potentially a procedure such as heart valve repair or replacement.  

If you would like to speak to one of our world-leading heart specialists about treatment options for a heart murmur, please contact our team to book an appointment.