Restrictive Cardiomyopathy

Definition

Restrictive cardiomyopathy refers to a set of changes in how the heart muscle functions. These changes cause the heart to fill poorly (more common) or squeeze poorly (less common). Sometimes, both problems are present.

Alternative Names

Cardiomyopathy - restrictive; Infiltrative cardiomyopathy; Idiopathic myocardial fibrosis

Causes

In a case of restrictive cardiomyopathy, the heart muscle is of normal size or slightly enlarged. Most of the time, it also pumps normally. However, it does not relax normally during the time between heartbeats when the blood returns from the body (diastole).

Although the main problem is abnormal filling of the heart, the heart may not pump blood strongly when the disease progresses. The abnormal heart function can affect the lungs, liver, and other body systems. Restrictive cardiomyopathy may affect either or both of the lower heart chambers (ventricles). Restrictive cardiomyopathy is a rare condition. The most common causes are amyloidosis and scarring of the heart from an unknown cause. It also can occur after a heart transplant.

Other causes of restrictive cardiomyopathy include:

• Cardiac amyloidosis
• Carcinoid heart disease
• Diseases of the heart lining (endocardium), such as endomyocardial fibrosis and Loeffler syndrome (rare)
• Iron overload (hemochromatosis)
• Sarcoidosis
• Scarring after radiation or chemotherapy
• Scleroderma
• Tumors of the heart

Symptoms

Symptoms of heart failure are most common. These symptoms often develop slowly over time. However, symptoms sometimes start very suddenly and are severe.

Common symptoms are:

• Cough
• Breathing problems that occur at night, with activity or when lying flat
• Fatigue and inability to exercise
• Loss of appetite
• Swelling of the abdomen
• Swelling of the feet and ankles
• Uneven or rapid pulse

Other symptoms may include:

• Chest pain
• Inability to concentrate
• Low urine output
• Need to urinate at night (in adults)

Exams and Tests

A physical exam may show:

• Enlarged (distended) or bulging neck veins
• Enlarged liver
• Lung crackles and abnormal or distant heart sounds in the chest heard through a stethoscope
• Fluid backup into the hands and feet
• Signs of heart failure

Tests for restrictive cardiomyopathy include:

• Cardiac catheterization and coronary angiography
• Chest CT scan
• Chest x-ray
• ECG (electrocardiogram)
• Echocardiogram and Doppler study
• MRI of the heart
• Nuclear heart scan (MUGA, RNV, PET)
• Serum iron studies
• Serum and urine protein tests

Restrictive cardiomyopathy may appear similar to constrictive pericarditis. Cardiac catheterization may help confirm the diagnosis. Rarely, a biopsy of the heart may be required.

Treatment

The condition causing the cardiomyopathy is treated when it can be found.

Few treatments are known to work well for restrictive cardiomyopathy. The main goal of treatment is to control symptoms and improve quality of life.

The following treatments may be used to control symptoms or prevent problems:

• Blood thinning medicines
• Chemotherapy (in some situations)
• Diuretics to remove fluid and help improve breathing
• Medicines to prevent or control abnormal heart rhythms

• Chemotherapeutic agents
• Medicines such as tafamidis that target abnormal proteins (amyloid fibrils) 
• Liver transplantation 

Additional treatments are also under investigation.

A heart transplant may be considered if the heart function is very poor and symptoms are severe.

Outlook (Prognosis)

People with this condition often develop heart failure that gets worse. Problems with heart rhythm or "leaky" heart valves may also occur.

People with restrictive cardiomyopathy may be heart transplant candidates. The outlook depends on the cause of the condition, but it is usually poor. Survival after diagnosis may exceed 10 years.

When to Contact a Medical Professional

Contact your health care provider if you have symptoms of restrictive cardiomyopathy.