Heart Murmur

Article contributed by Dr Chee Tek Siong, a Member of the Singapore Heart Foundation’s Board of Directors. He is also a Consultant Cardiologist in private practice.

When a doctor informs his patient that he has heard a heart murmur, the patient or the patient’s parents/guardian will feel uncomfortable or frightened almost immediately at the mention of this “heart disease”.


Ultrasound of the heart

What is a heart murmur?
A heart murmur is an unusual sound heard during a heartbeat. This is due to a rapid (sometimes turbulent) flow of blood through the heart chambers, heart valves or connection conduit between the blood vessels or a blood vessel and a heart chamber. Heart murmurs can be either innocent (sometimes also known as functional or physiological murmurs) or pathological.

What are innocent (or functional/physiological) heart murmurs?
These murmurs are usually due to an increase in blood flow velocity through a perfectly normal heart or blood vessels. Certain conditions such as anemia, fever, during or immediately after an exercise, pregnancy, hyperactive thyroid gland or a healthy child can cause a change in the blood flow velocity. In such conditions, the heart and its surrounding structures are perfectly normal. No treatment for the heart is necessary, however the underlying conditions such as fever and hyperactive thyroid gland have to be investigated and treated accordingly. These innocent heart murmurs are commonly present in most healthy children. Similarly, no treatment or further investigation is needed for the heart if the doctor is convinced that the murmurs are innocent.

What are pathological heart murmurs?
These murmurs are a result of defective heart valves, an abnormal connection between the right and left heart chambers or an abnormal conduit between the heart and its surrounding structures. As such, the doctor may need to conduct some investigations to ascertain the underlying cause, its severity and net effect on the overall heart function. The patient may require a follow-up and treatment, depending on the three factors listed earlier.

Examples of pathological heart murmurs

  1. Defective heart valves:
    1. Congenitally defective (e.g. bicuspid aortic valve, mitral valve prolapse);
    2. A result of our aging process (e.g. aortic sclerosis);
    3. Infection (e.g. rheumatic fever or infective endocarditis), or
    4. Secondary to systemic illnesses (e.g. rheumatoid arthritis, syphilis).These valves are either unable to close (regurgitation), open normally (stenosis), or a combination of both.
  2. Abnormal connection between the right and left heart chambers (e.g. atrial septal defect, ventricular septal defect) are usually congenital in origin. The defects may be simple, complicated or multiple in a person.
  3. Conduit connection between the heart chamber and the surrounding blood vessel or between two blood vessels (e.g. coronary arteriovenous fistula, patent ductus arteriosus) are also congenital in origin.

What to expect if there are heart murmurs?
If your doctor is certain that the heart murmurs are not due to an underlying heart problem (i.e. innocent murmurs), then no treatment or further investigation is necessary. The child or the patient can lead a normal life and no restriction on physical activity is needed.

Sometimes, when the doctor is less certain, he may conduct some of the following investigations, such as a chest X-ray, electrocardiogram (ECG), echocardiogram, exercise stress test, 24-hour ECG monitoring, computerised tomographic (CT) scan or cardiac catheterisation.

Further investigations and follow-ups are necessary if the murmurs are pathological. Depending on the underlying cause and the severity of the murmurs, the doctor may continue to monitor the patient’s condition if it is mild. He may also prescribe some medications, if the condition is moderate in severity.

However, if the underlying heart condition is severe or if it has resulted in deterioration of the heart function, more aggressive treatment may be necessary. For instance, an open heart surgery can be a repair or replacement operation and it has become a much safer procedure these days. Alternatively, some less invasive procedures have been successfully performed on selected patients (e.g. percutaneous transluminal mitral commissurotomy, transvenous aortic valve implantation).

Do I need to take antibiotics if I have heart murmurs?
Previously, doctors would advise patients who had pathological heart murmurs to take antibiotics before dental or other surgical procedures, in order to prevent an infection. However, this recommendation has now been changed. Most patients with heart murmurs are not required to take prophylactic antibiotics before undergoing dental or surgical procedures, except in a few rare situations.

Summary
A heart murmur is a worrisome “diagnosis” for some people. Most murmurs present especially in children and adults however, are innocent murmurs. No treatment is necessary and the affected person can lead a normal life and do physical activities. Even if the murmurs are pathological, many of the conditions are mild or moderate. As such, regular follow-ups with or without medications are all that is necessary. For those whose conditions are more severe surgery may be indicated.

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