Did you know that 1 in 500 adults may have cardiomyopathy? Many people don’t know they have it. Some types can weaken the heart and make everyday activities harder, so getting the right diagnosis and treatment matters.

Some of the main types of cardiomyopathy include hypertrophic and restrictive. Let’s look at the differences to understand how each condition affects the body, what symptoms it can cause, and possible treatment approaches. If you have questions about your diagnosis or symptoms, talk with your cardiologist.

Understanding Cardiomyopathy

Cardiomyopathy is the medical term for a disease of the heart muscle. Some people are born with cardiomyopathy because it runs in their family. Others develop it later because of another health condition, and in some cases, the cause isn’t known.

Symptoms of HCM and RCM can overlap, but people with RCM may also have weight gain, bloating, and nausea.

Many types of cardiomyopathy may weaken the heart muscle by enlarging, thickening, or stiffening its walls. When the heart’s structure changes, it may not be able to pump blood as powerfully or efficiently. These changes can cause an abnormal heartbeat and, in more serious cases, heart failure or cardiac arrest.

7 Differences Between Restrictive and Hypertrophic Cardiomyopathy

Two common types of cardiomyopathy are restrictive cardiomyopathy and hypertrophic cardiomyopathy. They each have a similar effect on the heart and body. Both types affect the heart’s ability to fill with enough blood before pumping, but they also have seven key differences.

1. Structural Changes

Restrictive cardiomyopathy (RCM) develops when the heart’s lower chambers (ventricles) become stiff because materials like abnormal proteins or excess iron build up in the heart muscle. When the heart relaxes between beats, the walls of the ventricles may not expand well to fill with enough blood for the rest of the body.

Hypertrophic cardiomyopathy (HCM) occurs when the heart muscle becomes thicker than usual, and muscle fibers are not properly aligned. A thick heart muscle can lead to smaller and stiffer ventricles that don’t fill with as much blood as a healthy heart.

2. Causes

HCM is more common than RCM. About 3 in 5 cases are inherited because it’s a dominant trait, which means only one biological parent needs the gene to pass it to their child. Other causes of HCM are unknown — it can develop at any age. More research is needed to understand why.

RCM is rare, accounting for only 5 percent of all cardiomyopathies. It’s typically a complication of another condition or treatment regimen where minerals, proteins, or chemicals enter the heart muscle when they shouldn’t. For example, people undergoing cancer treatments, like chemotherapy or radiation, are at higher risk of developing RCM. If you have one of the conditions below, you’re also more likely to develop RCM:

• Amyloidosis — In this condition, proteins collect in major organs, including your heart and kidneys.
• Sarcoidosis — This disease causes your immune system to form lumps in organs, including the heart, lungs, and skin.
• Hemochromatosis — Also called iron overload, this condition causes the body to store too much iron in tissues and organs (like the heart).

3. Symptoms

Up to 50 percent of people with HCM may not have symptoms because the walls aren’t thick and stiff enough to affect blood flow to the body. Others may experience the following left heart failure symptoms:

• Shortness of breath
• Chest pain, often with exercise
• Unexplained dizziness
• Fainting
• Feeling like the heart is beating quickly or fluttering

Symptoms of RCM are most noticeable when the condition is more severe and progressing toward heart failure. While people with RCM may have the left heart failure symptoms listed above, right-sided heart failure symptoms are also common. These symptoms include:

• Leg swelling
• Enlarged neck veins
• Weight gain
• Bloating
• Nausea

Keep in mind that these right-sided heart failure symptoms are also possible in rare, but severe cases of HCM.

4. Diagnosis

Research estimates that only 1 in 5 people who have HCM will get diagnosed because many people don’t have symptoms. Physicians sometimes catch the enlarged heart muscle on imaging while testing for a different health condition. If your doctor thinks you may have HCM, a cardiologist will run a few surveys and tests, including the ones below.

• Medical history — You may be asked about your family history of HCM and any symptoms you’ve been experiencing.
• Physical exams — They may listen for arrhythmias (abnormal heart rhythms or sounds, like a murmur) and take your blood pressure.
• Electrocardiogram (ECG) — This test checks your heart’s electrical activity and rhythm. You may have the test in the doctor’s office or wear a monitor at home to track your rhythm throughout the day.
• Imaging — Your doctor may order an echocardiogram or cardiac MRI to get a better picture of the heart’s pumping function, structure, and size.
• Cardiac catheterization — In some cases, a doctor may thread a thin tube (catheter) through a blood vessel to see how the blood is flowing through and around the heart.
• Sometimes, a doctor may also check blood flow and blood pressure in the pulmonary circulation.
• Blood tests — You may need blood tests to detect proteins in the blood that show if the heart is stressed or damaged.

If the doctor discovers HCM, they may recommend that your first-degree family members (like your children) get screened, since it’s genetic.

Restrictive and hypertrophic cardiomyopathy both affect the heart’s ability to fill with enough blood before pumping.

Testing for RCM can be slightly different. An ECG is often the first test because it can quickly rule out other cardiac conditions, although the cardiologist may also order an echocardiogram or cardiac MRI if needed. However, for an official diagnosis, many physicians perform an endomyocardial biopsy, in which they take a small sample of the heart muscle and examine the tissue.

5. Treatment

Treatment for HCM depends on your symptoms and how it’s affecting your life. If you have no symptoms and you’re not at risk for complications, your cardiologist may suggest monitoring your heart and how you feel. Regardless of your symptoms, your doctor might recommend the following based on their tests:

• Healthy lifestyle habits — You may need to quit smoking, improve your sleep quality, or manage your weight.
• Implantable cardioverter-defibrillator — This is a small device placed in the chest to help stop dangerous heart rhythms.
• Medication — Your cardiologist may suggest certain drugs that help ease symptoms, like beta-blockers, calcium channel blockers, or a newer drug called mavacamten (Camzyos).
• Surgery — You may need to undergo a procedure to improve the heart’s structure or place a device to monitor your heart’s rhythm.

On the other hand, there’s no specific treatment for RCM. Doctors typically focus on managing the underlying disease to minimize symptoms. If you’ve developed advanced symptoms or heart failure, then your doctor may look toward medications — and in advanced cases, a heart transplant.

6. Prognosis

The prognosis (outlook) for people with HCM varies with age, symptoms, and severity. It’s not usually life-threatening. With current care, most people with HCM can live a normal lifespan. Studies suggest the risk of dying from HCM-related causes is about 0.5 percent per year. However, HCM is the most common cause of cardiac arrest in athletes under age 35.

RCM is more complex, and the outlook depends on the underlying condition. It has the lowest survival rate of all cardiomyopathies.

7. Activity Restrictions

Anyone with cardiomyopathy should talk about any activity restrictions with their cardiologist. Exercise used to be heavily restricted for people with cardiomyopathy, resulting in additional risk factors associated with a sedentary lifestyle. More recent studies suggest that physical activity may not make cardiomyopathy worse, but a person’s exercise safety depends on symptoms.

RCM is rare, accounting for only 5 percent of all cardiomyopathies. HCM is more common than RCM.

Most people with HCM can typically do mild-to-moderately intense recreational exercise with clearance from their doctor. Athletes with HCM need to be more careful because 25 percent of all sudden cardiac deaths happen during physical activity (like sports).

One MyHeartDiseaseTeam member with HCM wrote that they love doing yoga. “You can do it in your own space and slow it down when you feel tired. I follow classes on YouTube and find it beneficial,” the member wrote. Other members prefer walking outside or on the treadmill: “It just makes me feel so much better afterward.”

People with RCM often get tired easily during exercise. What you can safely do may also depend on the condition causing it. Your care team will guide you based on your symptoms, and they may limit certain activities.

Talk to Your Cardiologist

Talk to your cardiologist if you have questions about your diagnosis or treatment. Different types of cardiomyopathy can weaken the heart and cause similar symptoms. Your care team can figure out which type you have and help you choose the right treatment plan.

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How were you diagnosed with restrictive or hypertrophic cardiomyopathy? Let others know in the comments below.