Cardiomyopathy is the medical term for any disease of the heart muscle, which is the layer in the heart wall that squeezes to make the heart pump. Hypertrophic means an increase in the size of the cells in an organ or tissue. So, hypertrophic cardiomyopathy (HCM) is an enlargement of the cells of the heart muscle.
When the heart muscle enlarges, it can become too thick or stiff. This can make it harder for the heart to pump blood and fill with blood correctly. There can also be an obstruction, blocking the flow of blood out of the heart as it pumps. With time, these changes can cause heart failure.
This article explains how doctors diagnose HCM and how they distinguish it from other similar heart conditions.
What is hypertrophic cardiomyopathy?
HCM is a genetic form of heart muscle disease. It affects about 1 in 500 adults, making it the most common form of inherited heart disease.
About half of those with HCM don’t know they have it because it does not always cause symptoms. When symptoms do appear, they are often mild and may not occur all the time. However, the condition can worsen with time, causing serious symptoms and complications. In rare cases, the first symptom of HCM is sudden cardiac arrest.
All these factors mean it’s important to talk with your doctor about your family history. You may be at risk of HCM if you have a family history of heart problems, especially if a family member died suddenly before age 40.
Diagnosing HCM takes careful evaluation. It is easy to misdiagnose as another condition, which can delay the right diagnosis. This is because the condition may be either asymptomatic or cause symptoms that resemble other conditions, such as:
Making your doctor aware of any family history of heart conditions can help them screen for HCM more effectively.
Diagnosing HCM can be tricky because other heart conditions share the same symptoms and may even show similar results on diagnostic tests. However, slight differences can give clues to the diagnosis.
Working with a heart specialist can help rule out other possible heart conditions, such as:
- amyloidosis
- aortic stenosis
- athlete’s heart
- Danon disease
- Fabry disease
- Friedrich ataxia
- hypertensive heart disease
- LEOPARD syndrome
Physical exam and symptoms
Your doctor may start by asking about any symptoms you have and any symptoms that show up during a physical exam.
A common first symptom of HCM is shortness of breath. Other symptoms can include:
- atypical heart rhythms
- chest pain
- unexplained dizziness
- fainting
- a lack of energy
- tiredness
- lightheadedness
- swelling in the feet or ankles
During a physical exam, your doctor will likely listen to your heart and lungs. The sounds they hear as your heart beats and blood flows through it can offer clues about your heart and lung health.
Imaging and other diagnostic tests
Several diagnostic tests for HCM can show what your heart muscle looks like and how well it is working.
If your doctor hears a murmur in your heart during a physical exam, they will likely refer you to a cardiologist. This type of specialist will order an EKG or an echocardiogram (echo).
An EKG tests your heart’s electrical activity. Whenever your heart beats, it releases an electrical signal, which causes its four chambers to squeeze so that it can pump blood into your body. An EKG uses painless electrodes stuck on your skin to measure these electrical signals and can show:
- the strength and timing of the electrical signals passing through the heart
- how fast your heart is beating
- if the rhythm of the heartbeat is steady or irregular
An echo is an imaging exam that shows your heart pumping blood. In HCM, it usually shows that the heart’s left ventricle (lower chamber) is larger than it should be.
Other tests may include:
- a cardiac CT angiography or cardiac MRI, which are detailed imaging exams of the heart
- an EKG, which uses painless electrodes stuck on your skin to measure the rate and rhythm of your heartbeat
- Holter monitoring or event monitoring, which records your heart’s activity over 24 hours or longer
- a stress test, which can show how your heart tolerates working harder during exercise
Doctors may recommend genetic testing to help diagnose HCM. It can help confirm the diagnosis and rule out other causes. Genetic testing is also recommended for parents, siblings, and children of someone with HCM.
The testing involves a simple saliva sample. However, it may not always give a clear answer. Because of this, it is important to work with a genetic counselor who can help you understand the results.
Hypertrophic cardiomyopathy (HCM) is a genetic heart condition that can look like many other kinds of heart disease. Careful examination can find clues to the correct diagnosis. A heart specialist usually diagnoses HCM using different kinds of testing. This may include genetic testing, with the help of a genetic counselor, to understand the results.