With each heartbeat, the heart normally contracts to pump blood out of the heart. When it relaxes, the heart is filled again with blood. Restrictive cardiomyopathy is a medical condition in which the muscles that are responsible for these actions become rigid or stiff. This often results in the heart's inability to relax and be filled with blood between each contraction. In restrictive cardiomyopathy, the heart muscles are usually not thickened and the heart may be slightly enlarged.
Patients with amyloidosis and hemochromatosis are frequently at increased risk of developing restrictive cardiomyopathy. This is because these conditions create excess materials that can be deposited in some parts of the body, including the heart muscles. The presence of these materials in the heart generally results in the development of rigid heart walls, which affects the function of the organ. There is an accumulation of an abnormal protein called amyloid in amyloidosis. In hemochromatosis, there is usually excess iron in the body.
Another cause of restrictive cardiomyopathy is scarring of the heart muscles. The cause of scarring is often unknown, in which case it is referred to as idiopathic myocardial fibrosis. Scar formation, however, may sometimes be seen after heart transplant surgery and after radiation treatment for cancer.
The stiffness of the heart muscles in restrictive cardiomyopathy may eventually lead to inefficient blood pumping. When this happens, blood supply to other vital organs like the lungs and liver becomes inadequate. Patients may develop an irregular heartbeat and palpitations. Other symptoms are usually associated with heart failure. These include shortness of breath, especially when lying down, edema, which is the swelling of the feet and hands, and ascitis, which is the collection of fluid in the abdomen.
Some patients may experience chest pains, faintness, loss of appetite, and decreased mental alertness. Their breathing difficulty is also often noted during exercise, because their stiff heart cannot pump enough blood for the body during such strenuous activities. Other signs that may indicate restrictive cardiomyopathy are bulging of the veins in the neck and in the legs.
Cardiologists are doctors who treat patients with heart conditions. They frequently base their diagnosis on the patients' medical history, their symptoms, findings during physical examination, and the results of several diagnostic tests. Tests for restrictive cardiomyopathy may include blood tests and other imaging tests, such as magnetic resonance imaging (MRI) and echocardiography.