Cardiomyopathy is a primary disease of the heart muscle as opposed to coronary heart disease which is a disease of the coronary blood vessels. Cardiomyopathy is due to many causes that are classified as primary and secondary.
Primary cardiomyopathy refers to a disease that is inherent in the muscle such as the inherited cardiomyopathy.
Secondary cardiomyopathy refers to a defect in the heart muscle that is secondary to a cause outside of the muscle such as hyperthyroidism. The abnormality in cardiomyopathy is decreased global function of the heart to pump out blood appropriately to the rest of the body. The function of the heart is to contract and squeeze out the blood followed by relaxation to allow the heart to refill with blood, which in medical terms are referred to as Systole (contraction) and Diastole (relaxation). In cardiomyopathies, one or both of these is globally affected throughout the chamber.
Dilated Cardiomyopathy
The chamber or chambers of the heart are enlarged, with the walls themselves being thin or normal. This leads to impaired pumping of the blood.
Hypertrophic Cardiomyopathy
The heart is enlarged only minimally, but the walls are much thicker with the chambers being normal or decreased in size. This heart is usually hyperactive but has great difficulty relaxing.
Restrictive Cardiomyopathy
This is a very rare form or cardiomyopathy due to rigid walls (e.g., amyloid). Most restricted cardiomyopathies are due to an infiltration such as amyloid or cancer.
Familial (Inherited) or Sporadic Cardiomyopathy
Familial cardiomyopathy refers to an inherited cardiomyopathy due to a genetic defect transmitted by one or more of the parents.
Sporadic cardiomyopathy is a genetic disease in which the defect arises de novo from some insult to that person’s genes (mutation). That person will now pass on the defective gene to their offspring and from that time on, it becomes a familial disease.