Heart Disease: Restrictive Cardiomyopathy

What Is Restrictive Cardiomyopathy?

Restrictive cardiomyopathy, the rarest form of cardiomyopathy, is a condition in which the walls of the lower chambers of the heart (the ventricles) are abnormally rigid and lack the flexibility to expand as the ventricles fill with blood.

The pumping or systolic function of the ventricle may be normal but the diastolic function (the ability of the heart to fill with blood) is abnormal. Therefore, it is harder for the ventricles to fill with blood, and with time, the heart loses the ability to pump blood properly, leading to heart failure

What Are the Symptoms of Restrictive Cardiomyopathy?

Many people with restrictive cardiomyopathy have no symptoms or only minor symptoms, and live a normal life. Other people develop symptoms, which progress and worsen as heart function worsens.

Symptoms can occur at any age and may include:

• Shortness of breath (at first with exercise; but over time it occurs at rest).
• Fatigue (feeling overly tired).
• Inability to exercise.
• Swelling of the legs and feet
• Weight gain
• Nausea, bloating and poor appetite (related to fluid retention).
• Palpitations (fluttering in the chest due to abnormal heart rhythms).

Less common symptoms:

• Fainting (caused by irregular heart rhythms, abnormal responses of the blood vessels during exercise, or no cause may be found).
• Chest pain or pressure (occurs usually with exercise or physical activity, but can also occur with rest or after meals).

What Causes Restrictive Cardiomyopathy?

A restrictive cardiomyopathy is not usually inherited and its cause is often unknown. Known causes may include:

• Build-up of scar tissue (often for no known reason).
• Build-up of abnormal proteins (amyloidosis) in the heart muscle.
• Chemotherapy or chest exposure to radiation.
• Excess iron (hemochromatosis) in the heart.
• Other systemic diseases (sarcoidosis).

How Is Restrictive Cardiomyopathy Diagnosed?

The size of the heart may remain normal with restrictive cardiomyopathy. In some cases, restrictive cardiomyopathy may be confused with constrictive pericarditis, a condition in which the layers of the pericardium (the sac that surrounds the heart) become thickened, calcified, and stiff.

Restrictive cardiomyopathy is diagnosed based on medical history (your symptoms and family history), physical exam, and tests: such as blood tests, electrocardiogram, chest X-ray, echocardiogram, exercise stress test, cardiac catheterization, CT scan, MRI and radionuclide studies (Multigated Acquisition Scan).

A myocardial biopsy occasionally is done to determine the cause of cardiomyopathy. During a myocardial biopsy, a small tissue sample is taken from the heart and examined under a microscope to examine the cause of the symptoms.

How Is Restrictive Cardiomyopathy Treated?

Treatment of this condition is difficult. Treatment is usually focused on treating the cause of this condition. Doctors recommend lifestyle changes and medications to treat heart failure.

What Lifestyle Changes Are Recommended?

Diet. Once you have symptoms such as shortness of breath or fatigue, you should restrict your intake of salt (sodium) to 2,000 to 3,000 mg per day. Follow this diet even when your symptoms abate.

Exercise. Your doctor will tell you if you may exercise or not. While exercise is generally good for the heart, people with this form of cardiomyopathy may experience fatigue and shortness of breath, even with minimal exertion. Therefore, experts recommend that you take frequent breaks, exercise at a time of day where you have the most energy and start slow, gradually building up strength and endurance. Heavy weight lifting is not recommended.