Hypertrophic cardiomyopathy is a genetic condition in which the heart fails to pump normally due to the muscular walls of the ventricles becoming abnormally thickened and stiff.
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The thickening reduces space within the ventricles, which are less able to completely fill with blood and pump it around the body properly. This can lead to angina, shortness of breath, lightheadedness and fainting. Hypertrophic cardiomyopathy is a very common condition and affects about 1 in 500 people in the UK.
Many people with this condition do not develop symptoms and can lead a normal life. However, in some cases, problems develop that significantly impact on daily living and even increase the risk of sudden cardiac death. The condition may cause atrial fibrillation, reduced blood flow from the heart and a leaky mitral valve that enables blood to pass back into the atria from the ventricles. Hypertrophic cardiomyopathy is the most common cause of sudden death in young people.
Hypertrophic Cardiomyopathy and Genetics
Since hypertrophic cardiomyopathy is a hereditary condition and runs in families, a doctor is likely to suggest screening if an individual reports having a first-degree relative with the condition. Hypertrophic cardiomyopathy is inherited in an autosomal dominant pattern, meaning that each child born to a parent who has the condition is at a 50% risk of also developing it. The screening may involve genetic tests and/or an echocardiography.
Genetic screening may not provide a conclusive answer because experts are not yet fully clear about how the genetics of this condition work. The mutation is only detectable in around half of families with the condition. For this reason, healthcare insurance may not cover this form of screening.
On the other hand, if genetic testing does reveal a gene mutation, a doctor may want to screen the parents, children or siblings of the patient to check whether they have also inherited the mutation and are at risk of developing the condition. The sooner this condition is diagnosed, the earlier treatment can begin to relieve symptoms and reduce the risk of dangerous heart rhythm abnormalities (arrhythmias) and sudden cardiac arrest.
If a patient who has a first-degree relative with the condition does not have genetic screening or if the test results are not definitive, then echocardiography may be advised. This test uses ultrasound waves passed through the heart structure to visualize the heart’s pumping action and see whether there is muscle thickening, obstructed blood flow or abnormal movement of the mitral valve. Adolescents and people who engage in athletic activities should be screened annually and screening once every five years is adequate for adults who are not athletes.