(RxWiki News) Familial restrictive cardiomyopathy (FRC) is a genetic heart disease in which the heart muscle stiffens and can't fully relax after each contraction.
In this condition, which can appear any time from childhood to adulthood, impaired muscle relaxation causes blood to back up in the upper chamber of the heart (the atria) and lungs, thereby reducing the amount of blood in the lower chambers of the heart (the ventricles).
In children, onset of FRC usually presents with a failure to gain weight or grow at a normal pace (failure to thrive), fatigue and fainting. Swelling or puffiness can appear in those severely affected by the condition, which can also cause lung congestion, enlarged liver, increased blood pressure and an abnormal buildup in the abdominal cavity (ascites). Children usually survive only a few years from diagnosis without treatment.
In adults, FRC typically appears with shortness of breath, fatigue, dizziness and exercise intolerance. Some may develop irregular heart beat and a sensation of fluttering or pounding in the chest (palpitations). Blod clots commonly form in adults with the condition. One-third of adult FRC patients do not survive more than five years past diagnosis without medical treatment.
Restrictive cardiomyopathies -- in which the relaxation of the heart muscle is impaired -- are the least common variants of cardiomyopathy, a fairly common condition which can involve a weak or enlarged heart muscle with impaired contraction.