Hypertrophic Cardiomyopathy: What is it? Symptoms, Causes, Diagnosis and Treatment

It is very common and can affect people of any age. It affects men and women alike.

It is a common cause of sudden cardiac arrest in young people, including young athletes.

Hypertrophic cardiomyopathy (HCM) occurs if the cells of the heart muscle enlarge and cause the walls of the ventricles (usually the left ventricle) to thicken.

The size of the ventricle usually remains normal, but the thickening can interfere with the blood flow of the ventricle. If this occurs, the condition is called obstructive hypertrophic cardiomyopathy.

Sometimes the septum (the wall that divides the left and right sides of the heart) thickens and swells into the left ventricle. This can block blood flow to the left ventricle.

So the ventricle must work hard to pump blood. Symptoms can include chest pain, dizziness, shortness of breath, or fainting.

Hypertrophic cardiomyopathy can also affect the heart’s mitral valve, causing blood to trickle back through the valve. Sometimes the thickened heart muscle does not block blood flow to the left ventricle.

In this case, it would be called non-obstructive hypertrophic cardiomyopathy. The entire ventricle can thicken, or the thickening can occur only in the lower part of the heart. The right ventricle can also be affected.

What are the symptoms of hypertrophic cardiomyopathy?

Many people with HCM have no symptoms or only minor symptoms, and they live normal lives. Other people develop symptoms, which progress and worsen as heart function worsens .

Symptoms of HCM can occur at any age and can include:

  • Chest pain or pressure (usually occurs with exercise or physical activity, but can also occur with rest or after meals).
  • Shortness of breath ( dyspnea ), especially with exertion.
  • Fatigue (feeling too tired).
  • Fainting (caused by irregular heart rhythms, abnormal blood vessel responses during exercise, or without cause).
  • Palpitations (fluttering in the chest) due to abnormal heart rhythms (arrhythmias), such as atrial fibrillation or ventricular tachycardia.
  • Sudden death (only occurs in a small number of patients).

How is HCM diagnosed?

Different tests can be used to diagnose hypertrophic cardiomyopathy:

Physical exam

Your doctor will hear a heart murmur or unusual heartbeat. Heart murmurs can occur if thickened heart muscle interrupts blood flow to your heart.


This is the most common diagnostic test for HCM. An echocardiogram creates pictures of your heart using sound waves. Your doctor will look for unusual movements.


An EKG is used to measure electrical activity in your heart. Hypertrophic cardiomyopathy can cause abnormal results.

Monitor Holter

A Holter monitor is a portable EKG that you can wear during the day. Your doctor will use it for 24 to 48 hours. This allows your doctor to see how your heart rate changes during different activities.

Magnetic resonance imaging (MRI)

A cardiac MRI uses a magnetic field to produce detailed images of your heart.

Cardiac catheterization

This test is responsible for measuring the pressure of blood flow in your heart and looking for blockages. To perform this test, your doctor will place a catheter in one of your arteries in your arm or near your groin.

The catheter is carefully passed through the arteries to the heart. Once it reaches the heart, a dye is injected so that your doctor can take detailed X-ray images.

What Causes Hypertrophic Cardiomyopathy?


Hypertrophic cardiomyopathy is typically an inherited condition. Faulty genes can cause the heart muscle to thicken. You have a 50 percent chance of inheriting one of these genes if one of your parents is affected by hypertrophic cardiomyopathy.

Inheriting the gene does not necessarily mean that you will have a symptomatic disease. HCM follows a dominant pattern of inheritance. However, symptoms do not always develop in people with the defective gene.

Other causes

Other possible causes of HCM include aging and high blood pressure. In some cases, the cause of HCM is never identified.

How is HCM treated?

There is currently no cure for hypertrophic cardiomyopathy, but there are treatments available to help manage its symptoms and prevent complications. Your treatment will depend on how your heart is affected and what symptoms you have.

You, as an MCH patient, may need:

  • Medicines – to help control your blood pressure, abnormal heart rhythms, or other symptoms you may have.
  • A pacemaker – to control your heart rate.
  • An implantable cardioverter defibrillator (ICD) – if you are at risk for a life-threatening abnormal heart rhythm.

How does hypertrophic cardiomyopathy affect people’s lives?

Research has shown that, with proper treatment and follow-up, most people with the condition live normal lives.

However, because there is a very small risk of a life-threatening abnormal heart rhythm, a small number of people with HCM are at risk of sudden cardiac death.

It is important to discuss this risk with your doctor, who may offer you medication or advise that you need an ICD if you are at higher risk.

You may need to make a few small lifestyle changes, like avoiding competitive sports, but you should be able to keep working and driving a car, for example.

However, you will not be able to drive a commercial or freight vehicle and may need to reconsider manual jobs that involve strenuous activity.

Who is affected by hypertrophic cardiomyopathy?

Hypertrophic cardiomyopathy affects between 600,000 and 1.5 million Americans, or one in 500 people.