Abnormal thickening of the muscular walls of the heart, which reduces its pumping efficiency
- Usually develops in adolescence but may be delayed until middle age
- In some cases, the condition is inherited
- Gender and lifestyle are not significant factors
In hypertrophic cardiomyopathy, the walls of the heart are excessively thick. This thickening prevents the heart from filling properly and may partially block the passage of blood from the heart, both of which reduce the pumping efficiency of the heart. The condition is usually inherited, but the exact cause is unknown. The disorder may cause sudden death in apparently healthy, active young people, but, sometimes symptoms do not develop until middle age.
What are the symptoms?
Symptoms of the disorder usually develop in adolescence. They first occur during exertion and may include:
Shortness of breath.
Palpitations (awareness of an irregular or abnormally rapid heartbeat).
As the disorder progresses, shortness of breath may be present at rest. In some cases, a life-threatening abnormal heart rhythm develops (see Arrhythmias). Hypertrophic cardiomyopathy may also distort the valve that sits between the left upper and lower chambers of the heart, causing it to leak (see Mitral incompetence).
In severe cases, the thickened heart walls may obstruct the blood flow out of the heart, which results in inadequate blood supply to the rest of the body. This situation is potentially fatal.
How is it diagnosed?
If your doctor suspects that you may have hypertrophic cardiomyopathy, he or she may arrange for an ECG to measure the heart’s electrical activity. You may also have echocardiography to image the heart. This shows the size of the heart and the thickness of the walls and is used to assess the degree to which output of blood from the heart is restricted. You may also have an exercise ECG (see Exercise testing) and monitoring of your heart rhythm for 24 hours while you carry out your normal activities (see Ambulatory ECG).
What is the treatment?
Treatment is aimed at improving the filling capacity of the heart using drugs such as beta-blockers and calcium channel blockers. If you have an abnormal heart rhythm, it may be treated with antiarrhythmic drugs. Some of the thickened muscle may be removed surgically. Alternatively, septal ablation may be recommended. In this procedure, a small amount of alcohol is injected into one of the arteries supplying blood to the thickened heart muscle. The alcohol causes part of the thickened muscle to die and shrink to a more normal size, reducing the amount of obstruction to blood flow out of the heart. In rare cases, a heart transplant may be considered. Hypertrophic cardiomyopathy increases your risk of developing infection of the lining of the heart or heart valves (see Infective endocarditis). Your doctor will advise you to maintain good oral hygiene to reduce the risk of infection. You will also be told how to recognize symptoms of infective endocarditis so that treatment can be given promptly if it does develop.
The disorder is sometimes inherited. For this reason, relatives of anyone with hypertrophic cardiomyopathy should be screened with echocardiography to see if they have the condition.
About 1 in 25 affected people die each year. The outlook is better if the symptoms are diagnosed and treated early.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.