Claire Mackie defines some common heart valve diseases and explains how underwriters view these conditions
The heart is a powerful muscular pump which keeps our bodies supplied with oxygen-rich blood. Within the heart are four valves which can open or close to control the flow of blood through the heart and its chambers in the right direction. Abnormalities in these valves result in poor heart function and if left untreated can result in heart failure.
A diseased or damaged valve can affect the flow of blood through the heart in two ways:
• The valve may not open fully and will obstruct the forward flow of blood. This is valve stenosis.
• If the valve does not close properly it will allow blood to leak backwards. This is called valve incompetence or regurgitation.
In heart disease the aortic and mitral valves are most commonly affected.
Mitral regurgitation
Mitral regurgitation occurs when the mitral valve fails to close properly causing blood to leak through the mitral valve back into the left atrium. In its mildest form, symptoms may go unnoticed, however as the regurgitation increases in severity it can put excessive strain on the heart causing it to become enlarged, less effective as a pump and more likely to beat in an abnormal way. The backflow of pressure may cause fluid to accumulate in the lungs and lower legs.
Usually, mitral regurgitation is asyptomatic, however symptoms may present in the form of shortness of breath, palpitations and fatigue warranting further investigation. Typically, the GP would listen to the heart sounds using a stethoscope for signs of the classic murmur across the apex of the heart. The next step would be to arrange an ECG, chest X-ray and echocardiogram in order to establish the nature and severity of the diseased valve.
Many people with mild mitral regurgitation have a completely normal life with no need for treatment. For others medication or surgery may be necessary. Medication is aimed at controlling and reducing the amount of work the heart has to do and also stabilise the rhythm. Some individuals may require a valve replacement where the valve is severely diseased or there is a poor response to medical treatment.
Valve operations are not risk free. Five in every 100 patients who have had surgery to replace a valve die within 30 days of the operation. The risk obviously varies from person to person but is strongly related to the heart's functional capacity at the time of surgery. Other surgical complications include heart failure, infarction and arrhythmia.
Mitral valve prolapse
Mitral valve prolapse is the most common heart valve abnormality, affecting between 5 to 20% of the population. It is more common in women and usually diagnosed between the ages of 20 and 40. This occurs when the valve loses its shape and becomes weakened or stretched resulting in failure of the valve to shut properly causing a backflow of blood. This causes a characteristic clicking sound or murmur which can be picked up on a routine medical examination. The condition is generally asymptomatic with no significant complicating features. Symptoms may include dyspnoea, fatigue, palpitations, atypical chest pain and panic attacks.
On detection of a murmur further investigations will be required to quantify the degree of mitral insufficiency. Such investigations include an ECG or preferably an echocardiogram which is the most useful non-invasive test to diagnose the presence of mitral valve prolapse. Most cases run a benign and often asymptomatic course however there may be progression to frank mitral regurgitation. Other complications include an arrhythmia (abnormal heart rate) and blood clots causing embolism. Defective heart valves are more vulnerable to bacterial infections entering the blood stream, therefore individuals need to take antibiotics as a precaution when they have surgery or major dental work.
Aortic stenosis
Aortic stenosis is caused by narrowing of the aortic valve with subsequent calcification, causing restriction of the flow of blood through it . Most often it is due to a congenital abnormality although rheumatic and degenerative changes can also be a factor.
The valve works well for many years and although a systolic murmur may be detected with a stethoscope or mild stenosis picked up on echocardiography, there are no symptoms. Gradually, over the years calcium is deposited on the valve causing it to narrow. Over a number of years the left ventricle enlarges to be able to force blood through the narrowed valve. Eventually, and this may not be until the patient is in their 60s or 70s, this compensation fails and signs of heart failure occur such as breathlessness, angina and dyspnoea. Sudden death is not uncommon. Once the disease has progressed to this stage the only appropriate treatment is valve replacement or valvuloplast (balloon widening of the narrowed valve).
Claire Mackie is a life and disability underwriter at Scottish Equitable Protect
