Cardiomyopathy: a disease of the myocardium that may be inherited, acquired, or secondary to another defect or disease. This leads to the inability of the ventricle to pump blood and may result in heart failure. In the pediatric setting, there are four major types:

Arrythmogenic: this results in a defect of the conduction tissue of the right atrium and right ventricle, causing dilatation, chamber enlargement, thinning of the right ventricular myocardium and possible aneurysms.

Dilated: the ventricles and possibly the atrium become thinned, dilated and oversized and are unable to pump blood sufficiently. If the ventricle is stretched too far, and Starlings law takes effect in the affected chamber or chambers, they may be unable to recover. Typically there is volume overload of the affected chamber.

Hypertrophic: pressure overload of one or both ventricles that causes them to become thick and inefficient. As the ventricle thickens, it pumps less blood per beat but works march harder to accomplish this. Look for such causes as aortic stenosis or LVOT obstructions.

Restrictive and constrictive: restrictive cardiomyopathies are the result of the myocardium becoming rigid and unable to fill completely with blood (preload). Constrictive cardiomyopathy it Is similar in nature, often the result of infections or other diseases, and may include such causes as pericarditis, tuberculosis or fungal infections.