What is Restrictive Cardiomyopathy?

Restrictive cardiomyopathy (RCM) is a disease of the heart muscle where the heart muscle becomes rigid and unable to relax and fill with blood. The function or squeeze of the heart may be normal, but the relaxation is abnormal. When the lower left chamber of the heart, called the left ventricle, is unable to stretch and fill with blood, pressure builds up causing abnormal heart rhythms and symptoms of heart failure. 

There are many conditions that can cause RCM. It can be inherited genetically, associated with other genetic, inflammatory or infiltrative conditions, acquired through the effects of certain medications, or its cause can be unknown (idiopathic).

Effects and Symptoms

Many individuals with RCM do not have any symptoms. Symptoms can develop at any age. RCM can cause heart failure symptoms in infants and children and can present as poor feeding or growth, excessive sweating with feeds or activity and fast breathing. In older children, it can cause fatigue, weakness and poor exercise tolerance. It can also cause dizziness or light-headedness, fainting, a persistent cough or palpitations (a feeling of fast, abnormal heart beats).

Diagnosis

Children who do not have symptoms are diagnosed through screening for a neuromuscular or genetic condition or they are screened because a close relative (a parent, sibling or child) has been diagnosed with cardiomyopathy. Others have shortness of breath during exercise and poor exercise tolerance. On physical examination, a murmur or gallop rhythm (an extra heart sound) may be heard when listening to the chest. 

An enlarged heart can be seen on chest xray. An echocardiogram can demonstrate markedly enlarged or dilated atria (upper chambers) that are often larger than the ventricles (lower chambers).

Management and Treatment

The treatment for children with RCM is focused on managing symptoms, preventing abnormal heart rhythms and delaying the progression of the disease. Regular follow up is needed with the cardiologist for monitoring. Exercise and activity restrictions may be recommended and are tailored on an individual basis. In severe cases that cannot be adequately managed with medications, a heart transplant is considered.

Adult and Adolescent Management

Women of child-bearing years are counseled about contraceptives and pregnancy. Though there have been reports of healthy pregnancies in women with RCM who have no symptoms, they are very rare. Normal changes in pregnancy will cause stress on the heart and may not be tolerated well by patients with RCM. A consultation and counseling with a cardiologist is necessary for those who have plans of getting pregnant.