What is a Heart Murmur?
During a physical examination, your doctor usually listens to your heart with a stethoscope. The stethoscope is placed on different parts of your chest to enable the doctor to hear the sounds your heart valves make as blood passes through your heart. Your heart has four valves which keep blood flowing in the correct direction through the heart. The valves open and close once during each heartbeat. Normally, the heart makes two sounds as your heart valves open and close – these sound like “lub-dub”. The first sound is heard when the valves between the upper and lower heart chambers (“mitral” and “tricuspid” valves) shut. The second heart sound is heard when the valves between the lower heart chambers and major blood vessels (“aortic” and “pulmonary” valves) close. A heart murmur is a ‘whooshing’ sound heard when there is turbulent or abnormal blood flow across one or more heart valves.
What causes a Heart Murmur?
A heart murmur may occur due to several possible causes. The most common causes include:
- Valvular heart disease, which is generally divided into:
- Valvular stenosis – a narrow or stiff valve, slowing forward flow of blood through the valve.
- Valvular regurgitation – a valve that does not shut completely, allowing blood to leak backwards in the heart.
- Non-cardiac conditions that cause increased blood flow across normal valves:
- Anaemia (blood’s inability to deliver adequate oxygen around the body)
- Hyperthyroidism (overactive thyroid gland)
- Congenital heart disorders – these are present from birth and are due to the heart and blood vessels failing to grow properly during fetal development
- Hypertrophic cardiomyopathy – a genetic condition that leads to thickening of the heart muscle which may lead to obstruction of blood flow through the heart
- Endocarditis – infection of the heart valves
What are symptoms that may be associated with Heart Murmurs?
Heart murmurs themselves do not cause you to feel any symptoms, and are often only picked up by your doctor during a routine physical examination. However, if the murmur is due to underlying heart disease, symptoms that may suggest underlying heart disease include:
- Shortness of breath or difficulty catching your breath, either during exertion or at rest
- Chest discomfort
- Heart palpitations (“heart racing” or beating irregularly)
- Light-headedness or dizziness
- Difficulty lying flat in bed due to shortness of breath
- Swelling of ankles or abdomen
How is the cause of a Heart Murmur diagnosed?
After your doctor takes a complete medical history and performs a physical examination to assess the clinical type and severity of the murmur, further tests are usually needed. These tests help your doctor to determine why the murmur might be present, which valve or part of the heart is involved, how severe the problem is and what treatment is required. These tests may include:
- Electrocardiography (ECG)
- Chest x-ray
- Blood tests
- Echocardiography (heart ultrasound)
- Exercise stress test
By repeating these tests over time, your doctor can see the progress of your underlying heart disease and help you make decisions about any changes in treatment.
What are the possible treatment options for Murmurs?
The treatment of heart murmurs depends on the underlying cause of the murmur. Some murmurs (e.g. flow murmurs during pregnancy) may need no specific treatment aside from regular monitoring by your doctor. If murmurs are due to underlying structural heart or valvular problems, then treatment may include medications or heart surgery, depending on the type and severity of heart disease.