Cardiomyopathies are diseases of the heart muscle, also known as the myocardium, in which the actual muscle cells and surrounding tissues are sick.
Cardiomyopathies can be primary, meaning the sickness mainly involves the heart.
They can also be secondary, meaning the sickness is a result of another disease or toxin and may also affect many organ systems within the body, including the heart.
Patients with cardiomyopathy will most commonly have a heart that looks normal but does not work well.
Cardiologists group cardiomyopathy into five categories:
- Dilated cardiomyopathy (DCM), also known as congestive cardiomyopathy: Dilated cardiomyopathy is the most common form of cardiomyopathy in children. In DCM, the heart becomes enlarged and does not contract or squeezes poorly.
- Hypertrophic cardiomyopathy (HCM): With hypertrophic cardiomyopathy, the heart muscle is thickened. Another name for this is idiopathic hypertrophic subaortic stenosis (IHSS). Hypertrophy, or thickening, particularly of the left ventricle, can make it hard for blood to flow through the heart and for the left ventricle to fully relax. Children with hypertrophic cardiomyopathy are also at increased risk for abnormal heart rhythms, or arrhythmias.
- Restrictive cardiomyopathy (RCM): With restrictive cardiomyopathy, the pumping chamber or ventricle is not able to relax properly. As a result, blood gets backed up into the upper chambers of the heart, or atria, and they become enlarged or bigger, while the lower pumping chambers, the ventricles, remain normal in size. This is a rare form of cardiomyopathy in children.
- Left ventricular non-compaction (LVNC): On echocardiogram, the heart muscle appears coarse and marked with fingerlike projections called trabeculations. It appears coarse and jagged instead of smooth and compact. It may be related to other forms of congenital heart disease but can occur on its own. A few patients may go on to have poor function and heart failure.
- Arrhythmogenic right ventricular cardiomyopathy (ARVC): The muscle of the heart is replaced by fat tissue over time and leads to dangerous heart rhythms. This form of cardiomyopathy is often hard to diagnose. It is usually first found when the patient has an abnormal rhythm. This is also sometimes referred to as arrhythmogenic right ventricular dysplasia (ARVD).