Cardiomyopathy

Any disease of the heart muscle that weakens the force of cardiac contractions, thereby reducing the efficiency of blood circulation. Cardiomyopathies may have an infectious, metabolic, nutritional, toxic, autoimmune, or degenerative cause. However, in many cases the cause is unknown. There are 3 main types. In hypertrophic cardiomyopathy, which is usually inherited, the heart muscle is abnormally thickened. In dilated cardiomyopathy, metabolism of the heart muscle cells is abnormal and the walls of the heart tend to balloon out under pressure. Restrictive cardiomyopathy is caused by scarring of the endocardium (the inner lining of the heart) or by amyloidosis. Symptoms of cardiomyopathy include fatigue, chest pain, and palpitations. The condition may lead to heart failure, symptoms of which include breathing difficulty and oedema. A chest X-ray may show enlargement of the heart, and echocardiography may show thickened heart muscle. A biopsy of heart muscle may reveal muscle cell abnormalities. Symptoms may be treated with diuretic drugs to control heart failure and antiarrhythmic drugs to correct abnormal heart rhythm. In many cases, heart muscle function deteriorates, and the only remaining option is a heart transplant.