(Diseases of the Heart Muscle)


Cardiomyopathy is a general term that refers to diseases of the heart muscle. In cardiomyopathy, the heart can be enlarged, and the muscle can be too thick or thin and may not squeeze as well as it should. The heart is less able to pump blood effectively and prone to heart failure, heart valve problems, and arrhythmias arising from either the top or lower chambers of the heart. Cardiomyopathy often goes undiagnosed, but it’s estimated that as many as 1 in 500 adults may have this condition.1

Cardiomyopathy can affect people of all ages, even children. We are discovering more about the genetic causes of the various kinds of cardiomyopathy. While cardiomyopathy is a serious condition, it's usually treatable. Treatment options include medication, surgery, implantable devices, and minimally invasive procedures. The type of treatment your doctor recommends will depend on the type of cardiomyopathy and the extent of the problem.

A diagram showing three different types of cardiomyopathy with a healthy heart for comparison.

Types of cardiomyopathy

There are different types of cardiomyopathy, including those that are congenital (present at birth) or acquired (developed during your lifetime). You could be born with cardiomyopathy but not be diagnosed until you’re older.

  • Dilated cardiomyopathy – In dilated cardiomyopathy, the heart muscle weakens and the heart becomes enlarged. As the heart becomes stretched, its lower chambers (ventricles) are less able to pump blood efficiently, and the enlargement can cause the heart valves to leak. Eventually, the heart is not able to pump enough blood to the body, and the lungs become congested, leading to heart failure. Abnormal heart rhythms may also result when the heart becomes enlarged. Dilated cardiomyopathy is the most common of all cardiomyopathies, usually occurring in adults younger than 50.2
  • Hypertrophic cardiomyopathy (HCM) – In HCM, the heart’s walls become thick and are unable to flex as they should. As a result, blood flow out of the heart may be blocked (obstructive HCM). Nonobstructive HCM occurs when the thickened muscle does not block blood flow out of the heart. HCM is a significant cause of both heart failure and sudden death as well as abnormal heart rhythms. It's the most common cause of sudden cardiac death among athletes who are believed to be healthy.3 HCM can have a genetic component and run in families.
  • Restrictive cardiomyopathy – In restrictive cardiomyopathy, which is more common in older people, the lower heart chambers grow stiffer and more rigid as the condition progresses. This occurs because abnormal tissue, which may include scar tissue, is replacing the regular heart muscle. As with other types of cardiomyopathy, the heart becomes increasingly ineffective at pumping blood and is more prone to heart failure and arrhythmias.
  • Arrhythmogenic right ventricular dysplasia (ARVD) – This rare form of cardiomyopathy occurs when the walls of the right lower chamber/ventricle of the heart die and are replaced by scar tissue. ARVD can disrupt the heart’s rhythms, causing arrhythmias, including Afib, and sudden cardiac arrest. ARVD mostly affects teens and young adults and is believed to be a hereditary problem.
  • Unclassified cardiomyopathy – There are other forms of cardiomyopathy that develop as a result of other conditions and can’t be grouped with the main types listed above.