Restrictive cardiomyopathy (RCM) is a heart condition in which the walls of the ventricles stiffen and lose their flexibility due to infiltration by abnormal tissue. As a result, the heart cannot fill adequately with blood and eventually loses its ability to pump properly. Restrictive cardiomyopathy is a rare type of cardiomyopathy. Restrictive cardiomyopathy typically arises from another disease, which occurs elsewhere in the body. In the United States, restrictive cardiomyopathy is most commonly related to the following: amyloidosis, in which abnormal protein fibers (amyloid) accumulate in the heart's muscle; sarcoidosis, an inflammatory disease that causes the formation of small lumps in organs; and hemochromatosis, an iron overload of the body, usually due to a genetic disease.
Although rhythmicity and contractility of the heart may appear to be normal in restrictive cardiomyopathy, the stiff walls of the atria and ventricles (heart chambers) keep them from adequately filling, reducing preload and end-diastolic volume. So blood flow is reduced, and blood that would normally enter the heart is backed up in the circulatory system. In time, restrictive cardiomyopathy patients develop diastolic dysfunction and eventually heart failure.
Symptoms of restrictive cardiomyopathy include symptoms of congestive heart failure: weakness, fatigue, and breathlessness. Swelling of the legs, caused by fluid retention, occurs in a significant number of patients. Other symptoms include nausea, bloating, and poor appetite, probably because of the retention of fluid around the liver, stomach, and intestines. Therapy for restrictive cardiomyopathy is limited. Diuretics may help relieve symptoms. Calcium Channel Blockers may improve diastolic function in selected individuals. Heart failure resulting from restrictive cardiomyopathy will usually eventually have to be treated by cardiac transplantation.