What is restrictive cardiomyopathy?
Restrictive cardiomyopathy is the rarest of the cardiomyopathies. It is characterised by increased stiffness of the heart muscle, usually due to scar tissue, which prevents adequate filling of the chambers of the heart. The actual pumping action of the heart is usually normal.
The cause of restrictive cardiomyopathy is unknown in the majority of cases. In some cases it may be due to very rare conditions which cause infiltration of the heart (see below), infection and drugs. In advanced cases, reduced filling of the left heart chamber causes a build up of pressure and occasionally fluid in the lungs. Reduced filling of the right heart causes a build up of pressure and fluid in the abdomen and legs.
Conditions that can cause restrictive cardiomyopathy
- Infiltrative disorders
- Endomyocardial fibrosis
- Carcinoid syndrome
- Systemic sclerosis
- Radiotherapy to the chest
The main symptoms of restrictive cardiomyopathy are breathlessness, fatigue and ankle swelling. In some cases the diseased heart may beat rapidly or with an abnormal pattern resulting in palpitations. Occasionally the rhythm disturbance is severe enough to cause “blackouts”. Sudden death is a recognised feature.
The diagnosis is confirmed with a combination of ECG and Echocardiography. Further evaluation is performed with a cardiac MRI scan. In some cases the patient will undergo an invasive cardiac catheter study to measure the pressures within various chambers of the heart.
A familial form of the disease is recognised but it is not known how common this is.
Maintaining the balance to keep the circulating fluid volume adequate is the mainstay of treatment. This is with a variety of drugs including diuretics and drugs that control rhythm disturbances of the heart.