What is valvular heart disease?
The hearts four valves play a very important role in ensuring blood flows in the correct direction through the heart. The valves are:
- The tricuspid valve.
- The pulmonary valve.
- The mitral valve.
- The aortic valve.
Valves at the entrance to the large chambers of the heart, (the tricuspid and the mitral valves) ensure that blood can flow only into the ventricles.
The pulmonary and aortic valves allow blood to flow out of the ventricles and into the pulmonary artery and aorta.
In patients with valvular heart disease the damaged valve or valves affect the flow of blood. This can be in two ways:
- If a valve fails to close properly it will allow blood to leak backwards. This is called valve regurgitation. For example, if the mitral valve leaks as the left ventricle contracts, instead of all the blood leaving the heart through the aortic valve, some will leak back into the left atrium. If this is severe enough it can put a backpressure on the lungs.
- If a valve fails to open properly it obstructs the flow of blood. This is called valve stenosis. For example if the aortic valve becomes stenosed the heart will need to pump harder to force the blood past the valve. This can cause the heart muscle to become thickened.
Any of the valves can become regurgitant or stenosed and both can put an additional strain on the heart. Although many patients have few or no symptoms, some patients develop:
- Chest pains
- Swelling of the legs
The symptoms of valvular heart disease will vary depending on which valve is affected. Even after a valve problem has been diagnosed, patients may go many years without developing any symptoms.
What causes valvular heart disease?
The main causes of disease or damage to the heart valves are:
- Congenital heart disease, that is being born with an abnormal valve or valves.
- The long-term effects of rheumatic fever. Even though rheumatic fever is now uncommon in the United Kingdom (although it is still common in other parts of the world), some middle-aged or elderly people may have had the disease unknowingly. Rheumatic fever most commonly affects the aortic or the mitral valves.
- Part of the natural ageing process; the valves may thicken and restrict the flow of blood.
- As a result of other disease affecting the heart. For example, if the heart becomes enlarged for whatever reason, it can cause the mitral valve leaflets to be pulled further apart than normal. This prevents them from closing properly when the ventricle contracts, and so causes the valve to leak.
- Previous infection of the heart valves (called endocarditis); although rare, it can leave the heart valves damaged.
How is valvular heart disease diagnosed?
Leaking or narrowed heart valves cause the flow of blood to be turbulent within the heart. This turbulent blood flow is noisy and can be heard by your doctor with a stethoscope. The extra noise is called a heart murmur. Heart murmurs do not always signify damaged valves as they can also be heard in completely normal hearts.
Further tests will probably be required to assess the significance of any murmur:
- Blood tests to look for anaemia or thyroid disease.
- A chest X-ray to see if the heart is enlarged or if there is congestion of the lungs.
- An electrocardiogram (ECG) to look at the rhythm and electrical activity of the heart.
- An ultrasound scan of the heart, called an echocardiogram. This is a painless test that provides important information about the way the heart is working. It provides pictures of the heart in motion and allows the doctor to assess the pumping action of the heart and how the heart valves are working.
Cardiac catheterisation, an X-ray/dye procedure done under local anaesthetic that provides information about pressures in the heart, the function of the heart muscle, valves and arteries may be necessary to assess the problem in more detail.
How is valvular heart disease treated?
Other than having regular checks on the valves, many patients with valvular heart disease require no treatment.
It is very important to be aware that any heart valve that is abnormal is susceptible to infection. This rare but potentially dangerous condition is called endocarditis. To reduce the risk of this infection:
- Ensure that your teeth and gums are healthy.
- Tell your dentist and doctors that you have a heart valve problem. If appropriate, they will then give you antibiotics before any treatment being considered.
Patients will usually have a yearly check-up. Even in the absence of symptoms this is important so that any potential problems can be detected and treatment started in the hope of preventing symptoms.
Medication may be necessary to control symptoms:
- Diuretics (commonly known as ‘water tablets’) help the body to lose salt and water through the kidneys and help relieve the build-up of fluid
- ACE-inhibitors act by dilating blood vessels in the body. By doing so, they reduce the work of the heart each time it pumps blood into the circulation. Unfortunately, not all patients are suitable for, or able to tolerate, ACE-inhibitors.
- Digoxin can be useful for patients with irregular heartbeats, to control the speed of the heart.
- Beta-blockers slow the speed and the force of the heartbeat and reduce the heart’s workload.
When the mitral valve or pulmonary valves becomes narrowed, it is sometimes possible to stretch the valve with a balloon introduced into the circulation from the groin. This procedure is done under local anaesthetic and is known as ‘valvuloplasty’.
If medication alone is not sufficient to control the symptoms from a leaking or narrowed valve, surgery may be needed to replace (or occasionally to repair) the damaged valve. If surgery is needed, you may be advised to have this done before any permanent damage to the heart occurs. This can be a very complex decision. It may even be advised at a time when you are experiencing very few symptoms.