Cardiomyopathy is a cardiac muscle disease that affects the ability of the heart to work as the pump organ in the human body.

Cardiomyopathy can be classified into primary and secondary cardiomyopathies.

Primary cardiomyopathy is a cardiac muscle disease with no known cause. They affect the ventricular muscles of the heart. They are further classified into:

  1. Idiopathic dilated cardiomyopathy.
  2. It's causes are unknown. However some possible causes such as myocarditis caused by virus, damage from toxins, hereditary mutations, and chronic alcoholism have been suggested.

    The size and weight of the heart is usually increased. All the four chambers of the heart are dilated and hence the heart appears globular. The walls of the ventricles may be thickened but cannot be observed because the ventricles are dilated. There's thickening of the endocardium and deposition of mural thrombi in the atria and ventricles. Cardiac valves are normal.

  3. Idiopathic hypertrophic cardiomyopathy.
  4. In this also, the size and weight of the heart is increased. The venticular volume could be smaller or normal. The myocardial is hypertrophied, i.e it's sizes of the cells have increased without an increase in their number. Hypertrophy occurs more in the interventricular septum.

    Symptoms such as angina, dyspnoea, congestive heart failure and sudden death are seen after an intensive physical exercises.

  5. Idiopathic restrictive cardiomyopathy
  6. The ventricular volumes are decreased and therefore ventricular filling is restricted. This is it's distinctive characteristic. The diastole of the heart is also abnormal.

Secondary cardiomyopathy is a cardiac muscle disease with a known cause. These causes range from congestive and restrictive factors to hypertrophic factors.

Secondary cardiomyopathy does not however include myocardial diseases of well known causes, for example ischaemia, hypertension, valvular heart disease, pericarditis, congenital heart diseases and inflammatory diseases involving the heart.

They are mainly those having a connection to nutritional disorders, chemical toxin, drugs, metabolism disorders, neuromuscular disorders, infiltrations and diseases of the connective tissue.