Restrictive cardiomyopathy

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Restrictive cardiomyopathy includes a group of heart disorders in which the walls of the ventricles (the two lower chambers of the heart) become stiff, but not necessarily thickened, and resist normal filling with blood between heartbeats.

Restrictive cardiomyopathy may occur when heart muscle is gradually infiltrated or replaced by scar tissue or when abnormal substances accumulate in the heart muscle.
Shortness of breath, fluid accumulation in the tissues, abnormal heart rhythms, and awareness of heartbeats are common symptoms.
The diagnosis is based on results of a physical examination, electrocardiography, echocardiography, magnetic resonance imaging, cardiac biopsy, and cardiac catheterization.
Treatment is not often helpful, although sometimes doctors are able to treat the cause.

Cardiomyopathy refers to progressive impairment of the structure and function of the muscular walls of the heart chambers. There are three main types of cardiomyopathy. In addition to restrictive cardiomyopathy, there are dilated cardiomyopathy and hypertrophic cardiomyopathy (see also Overview of Cardiomyopathy).
The term cardiomyopathy is used only when a disorder directly affects the heart muscle. Other heart disorders such as coronary artery disease and heart valve disorders, also can eventually cause the ventricles to enlarge and heart failure. However, doctors do not classify the heart muscle problems caused by those disorders as cardiomyopathies.
Restrictive cardiomyopathy is the least common form of cardiomyopathy and shares many features with hypertrophic cardiomyopathy. Its cause is usually unknown.
There are two basic types of restrictive cardiomyopathy:

The heart muscle is gradually replaced by scar tissue.
Abnormal substances accumulate in the heart muscle.

A congenital form of restrictive cardiomyopathy occurs in infants who have endocardial fibroelastosis. In this rare disorder, a thickened layer of fibrous tissue lines the left ventricle.