Hypertrophic cardiomyopathy (HCM) is a genetic disease of the heart. Not everyone with the disease will experience symptoms, but early detection is important.
HCM is a disease that causes the walls of the heart’s chambers to thicken. This can cause the walls to become stiff, reducing the amount of blood being taken in and pumped throughout the body.
Most commonly, the disease is due to a gene mutation that can run in families. This is often known as familial hypertrophic cardiomyopathy.
Some people with HCM may experience no symptoms or only experience symptoms when the disease has progressed.
Learn more about HCM, how a person can inherit it, symptoms to look out for, and how doctors diagnose the condition.
Not everyone with HCM will experience symptoms. Some people may only experience them when they exert themselves or exercise. Other people may not have symptoms in the early stages of HCM but may develop some as the disease progresses.
Possible symptoms include:
- pain in the chest — especially during exercise or physical exertion
- abnormal heart rhythms — also called arrhythmias
- shortness of breath
- swelling of the abdomen, ankles, feet, and legs
These symptoms may worsen over time and affect quality of life and a person’s ability to function.
As the disease progresses, it may cause other health issues.
- atrial fibrillation
- blood clots
- complications related to the heart
- heart failure
- sudden cardiac arrest
In North America, HCM is the
Parents can pass HCM on to children. This is known as familial hypertrophic cardiomyopathy.
Estimates suggest that familial HCM affects 1 in 200 people globally. In the United States, it is the most common genetic heart disease.
Typically, inherited HCM begins in adolescence or young adulthood, but it is possible for the disease to develop at any life stage.
Even in one family, symptoms of HCM can be variable, and many people will have none at all. Those that do have symptoms of familial HCM may only experience them mildly.
Familial HCM is due to variants or mutations in one of several potential genes that can cause the condition.
This can happen through a phenomenon known as autosomal dominant inheritance. This means a genetic condition, such as familial HCM, can be passed from just one parent with a genetic mutation to a child.
A child with a parent with a mutated gene also has a 50% chance of inheriting that gene.
In most cases, a person with familial HCM has one parent with the condition.
It is also possible for HCM to occur in people without a family history. This is known as nonfamilial hypertrophic cardiomyopathy.
Some people may not know they have HCM, as it does not always show symptoms.
Many people will not experience symptoms until the disease has progressed.
In many cases, people with HCM may be asymptomatic or only mildly symptomatic but may seek medical attention due to family history or an abnormal electrocardiogram (ECG).
Some people may have experienced progressively worsening intolerance to exertion, lightheadedness or fainting during or after exertion, or when dehydrated.
Recognizing the symptoms of HCM — if any appear — is important for diagnosis.
Reaching a diagnosis early on can be helpful, as treatment may be most effective in the early stages.
It is not always easy to reach an early diagnosis. This is because a person may be unaware they are experiencing HCM due to a lack of symptoms. Sometimes, a person may also become used to their limitations and may not take symptoms seriously.
While it is possible to live a typical life with HCM, the condition can also raise the risk for other serious complications.
Identifying HCM as soon as possible is important. This is because, in some cases, the first indication that HCM is present can be sudden cardiac death.
A doctor may undertake several steps to diagnose HCM.
- physical exams, including listening to the heart and lungs with a stethoscope
- ECG to check the electrical activity in the heart
- exercise test, which involves an ECG when a person is exercising on a treadmill or exercise bike
- echocardiogram, a scan showing the structure of the heart and how it pumps
- MRI to capture a detailed image of the heart
In some cases, a doctor may recommend genetic testing if HCM runs in families. If a person receives a diagnosis of HCM, it is important that any close relatives, such as children, siblings, and parents, undergo heart tests.
Identifying the disease early on can lead to prompt treatment, which can mean better outcomes for the person with the disease.
HCM is a disease that causes the walls in the heart’s chambers to thicken. This can reduce blood flow to and from the heart.
Typically, a person inherits HCM, and a parent may pass it to their child.
Not everyone with HCM will experience symptoms, but early diagnosis is important due to the risk of complications and sudden cardiac death.
Possible symptoms may include heart palpitations, dizziness, chest pain, and shortness of breath.
Immediate family members of a person with HCM should have a heart checkup, and doctors may advise families to undergo genetic testing.