Restrictive cardiomyopathy

Alternative names

Cardiomyopathy - restrictive; Infiltrative cardiomyopathy

Definition

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.

Causes, incidence, and risk factors

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.

Symptoms

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

Signs and tests
An examination may show signs of heart failure with fluid backup into the lungs or the systemic circulation (the extremities, gastrointestinal tract, and liver). The neck veins may be distended. Listening to the chest with a stethoscope (auscultation) may show lung crackles and may show abnormal or distant heart sounds.

Tests that may indicate restrictive cardiomyopathy (by showing symmetrical thickening of the ventricle walls and signs of abnormal heart function such as decreased cardiac output, and/or elevated end diastolic pressure) include:

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