I've been hearing a lot about cardiomyopathy these days.  I know of children with heart defects that develop cardiomyopathy and other people that are suddenly diagnosed with it later in life with no heart defect.  Are there different types of Cardiomyopathy and what do they mean?

In the broadest sense, cardiomyopathy means heart muscle disease.  There are many forms such disease can take. For some, the muscle may become abnormally enlarged or thickened, for others, it may be thinned, and in others, the wall thickness may be normal but stiff. The function of the heart may be normal (at least at first), but frequently is weakened over time, often causing heart failure and the backup of blood into the lungs or the rest of the body.  In many cases, the cardiomyopathy may affect only one chamber of the heart (usually one of the lower chambers), but in severe cases can affect the others.

There are 3 different types of cardiomyopathy:  dilated, hypertrophic and restrictive. 

Dilated Cardiomyopathy is a condition where the heart's ability to pump blood is decreased because the heart cavity becomes enlarged and doesn't pump normally.  This then causes the amount of blood pumped out of the heart with each beat to be less than it should be.  The more slowly the blood flows through the heart the more likely that blood clots can form.  Another complication is arrhythmias and electrical disturbances in the heart.

Hypertrophic Cardiomyopathy has two different forms:  obstructive and non-obstructive. Thickening of the heart muscle at the septum between the ventricles, below the aortic valve (obstructive), eventually leading to the stiffening of the walls of the heart and abnormal function of the aortic and mitral valve function.  The increased size of the septum causes the blood to be obstructed during outflow.  The second type, non-obstructive, is where the left ventricle enlarges or hypertrophies.  The enlargement of the ventricle is what causes the amount of output from the left ventricle to decrease.

Restrictive Cardiomyopathy, also the rarest form, is a condition where the walls of the lower heart are abnormally rigid and lack the flexibility to expand as the ventricles fill with blood.  The pumping function (systolic function) may be normal, but the diastolic function (where the heart fills with blood) is abnormal.  With time this leads to heart failure.

For more information on the signs and symptoms, causes and treatment of the various types of cardiomyopathy follow these links:

http://www.webmd.com/heart-disease/guide/muscle-cardiomyopathy

http://www.americanheart.org/presenter.jhtml?identifier=4468

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