Restrictive cardiomyopathy refers to a group of disorders in which the heart chambers are unable to fill with blood properly because of stiffness of the heart. In restrictive cardiomyopathy, the heart is normal in size or only slightly enlarged, but it cannot relax normally during diastole (that is, the time between heartbeats in which the blood returns from the body to the heart).

Later in the disease, the heart may not pump blood efficiently. The abnormal heart function can affect the lungs, liver, and other body systems. Restrictive cardiomyopathy may affect either or both ventricles and may or may not be associated with a disease of the heartmuscle.

The most common causes of restrictive cardiomyopathy are amyloidosis and idiopathic myocardial fibrosis (a scarring of the heart of unknown cause). It frequently occurs after a heart transplant.

Other causes of restrictive cardiomyopathy include sarcoidosis, hemochromatosis, radiation fibrosis, and various tumor infiltrations of the heart. More rarely, restrictive cardiomyopathy is caused by diseases of the endocardium (the lining of the heart) such as endomyocardial fibrosis and Loeffler's syndrome.

• Excessive tiredness (fatigue)
• Swelling of the feet and ankles
• Cough
• Difficulty breathing
  • especially with exertion
  • at night
  • when lying flat
• Easily fatigued (poor tolerance of exercise)
• Swelling of the abdomen

• ECG (electrocardiogram)
• Echocardiogram and Doppler study
• Coronary angiography
• Chest X-ray
• Chest CT scan
• Chest MRI scan

Restrictive cardiomyopathy may be hard to differentiate from constrictive pericarditis. A biopsy of the heart muscle may be used to confirm the diagnosis.

A cardiac catheterization procedure can sometimes help differentiate the two cardiomyopathies by performing simultaneous left and right heart catheterization. In some cases, surgical exploration and biopsies are the only means to definitely distinguish restrictive cardiomyopathy from constrictive pericarditis.

Little therapy is known to be effective for the treatment of restrictive cardiomyopathy. The goal of treatment is to control symptoms and to improve the quality of life.

Various medications may be used to control symptoms. Diuretics may help somewhat in removing fluid, which can improve breathing. Depending on the underlying heart disease, some patients with restrictive cardiomyopathy may benefit from steroids or chemotherapy. A heart transplant may be considered if the function of the heart is very poor.