What is cardiomyopathy?

Cardiomyopathy (pronounced card-ee-oh-my-OP-ah-thee) is a disease of the heart’s muscular wall, called the myocardium. It can also be a change in the heart that causes it to lose its pumping strength.

There are 3 main kinds of cardiomyopathy: 

  • Dilated cardiomyopathy: the heart muscle is weakened and the heart becomes enlarged and stretched.
  • Hypertrophic cardiomyopathy: the heart muscle is too thick, which can cause a problem in the way the heart fills with blood and/or how it pumps blood out to the body.
  • Restrictive cardiomyopathy: the heart muscle becomes very stiff so it is harder for the lower chambers of the heart (ventricles) to fill with blood between heartbeats. 

In each case, cardiomyopathy reduces the heart’s ability to pump blood effectively and can lead to congestive heart failure.

  • The most common kind of cardiomyopathy in children is dilated cardiomyopathy. Viral infections (viruses) are a common cause. These infections can irritate the heart muscle (a condition called myocarditis) and weaken it. To try keeping up with the body’s need for blood and oxygen, the heart works harder and gets bigger.

    Other forms of dilated cardiomyopathy are genetic, meaning it can be passed down from parents to children in their genes and runs in families. Sometimes, no cause can be identified. Doctors call this “idiopathic” dilated cardiomyopathy.

    Hypertrophic cardiomyopathy is usually caused by a problem with 1 or more genes that are involved with heart muscle development. Some babies born with this type of cardiomyopathy show signs of an abnormal heart at birth, but in many people, it is not diagnosed until later in life. Hypertrophic cardiomyopathy can also develop after birth because of some other health problem, such as acromegaly (a hormone problem that causes excess growth).

    Restrictive cardiomyopathy is the least common kind. It is rare in children and is sometimes associated with a gene problem, but often no cause is identified. The condition can occur in babies born with an unusually thick lining in their heart. It can also develop in children if another condition causes scar tissue or some other kind of cell to build up in their heart muscle. One example would be a tumor that invades the heart.

Cardiomyopathy at Seattle Children’s

  • Seattle Children’s Heart Center is one of the best pediatric cardiology programs in the United States and is the top-ranked program in the Northwest, according to U.S. News & World Report. Our program has been named an Accredited Center of Care by the Children’s Cardiomyopathy Foundation (CCF), a national nonprofit committed to improving the health outcomes and quality of life for children with cardiomyopathy.

    With more than 40 pediatric cardiologists, we have experience diagnosing and treating every kind of heart problem.

    Our heart team has treated many children with cardiomyopathy. Our Heart Failure Program is the only subspecialty of its kind in the Northwest. We have extensive experience with the diagnosis and treatment these patients may require, including medicines, a pacemaker, a defibrillator or a ventricular assist device.

    Seattle Children’s has been treating children since 1907. Our team members are trained in their fields and in meeting the unique needs of children. For example, the doctors who give your child anesthesia are board certified in pediatric anesthesiology. This means they have extra years of training in how to take care of kids. Our child life specialists know how to help children understand their illnesses and treatments in ways that make sense for their age.

  • When you come to Seattle Children’s, a team of people will take care of your child. The cardiomyopathy and heart failure team includes not only your cardiologist (heart doctor), but also a group of specially trained heart failure nurses, geneticists with special interest in genetic cardiomyopathies, cardiac nutritionists, child life specialists and social workers.

    If your child requires hospitalization, care will be provided by specialized pediatric cardiac nurses, cardiac intensive care doctors (if your child is very sick), neonatologists, pulmonologists (lung doctors) and others, if their expertise is needed. We work together to meet all of your child’s health needs and help your family through this experience.

    Read more about the supportive care we offer.

Symptoms of Cardiomyopathy

Babies with cardiomyopathy may have these symptoms: 

  • Breathing difficulty (working hard to breathe)
  • Having poor appetite or trouble feeding
  • Failure to thrive 

In older children, the first symptoms are often shortness of breath when active and feeling more tired than normal. Some children develop arrhythmia or palpitations. Other possible symptoms include fainting and chest pain.

If your child has an infection that causes cardiomyopathy, you may first notice symptoms of the infection. These symptoms can include fever or chills or feeling weak or achy.

As the heart gets weaker, other symptoms of congestive heart failure may develop, such as difficulty breathing, poor appetite with nausea or vomiting, or edema.

Diagnosing Cardiomyopathy

To diagnose this condition, your doctor will examine your child and use a stethoscope to listen to their heart.

The doctor will ask for details about any symptoms your child has, their health history and your family health history.

To get more information about how their heart looks and works, your child will need some tests. Your doctor may use echocardiography and an electrocardiogram to aid in the diagnosis. Sometimes the doctor needs more information and will order chest X-rays or an MRI (magnetic resonance imaging) of the heart.

Many times, lab tests (blood draws) are needed to help identify a cause for the cardiomyopathy and to assess how the body’s other organ systems are handling the heart failure. In some cases, cardiac catheterization will be needed.

Treating Cardiomyopathy

Cardiomyopathy is usually treated with medicines. Some children may need a pacemaker or defibrillator. Some children’s hearts may be so weak that they require a machine (ventricular assist device) to help do the work of the heart. This is called mechanical circulatory support. In rare cases, a heart transplant is needed.

If doctors can find an underlying cause, such as an infection or hormone problem, they will treat this, too. Sometimes no underlying cause can be found.

  • To help the heart pump better, doctors use medicines like these: 

    • Angiotensin-converting enzyme (ACE) inhibitors, which reduce the workload on the heart and can slow the progression of the cardiomyopathy.
    • Beta-blockers, which have many of the same effects as ACE inhibitors and will also slow the heart rate.
    • Digoxin, which makes the heart beat slower and with more force.
    • diuretic (such as furosemide) can help the kidneys rid the body of extra water. This lowers the amount of fluid in the lungs and other tissues and may improve heart failure symptoms.
    • Anticoagulants, or anticlotting medicines, can help prevent or dissolve clots that might form in the heart. When the heart is enlarged and weak, blood flow is slower and may lead to clot formation.
    • Medicines that correct the heart rate or make an irregular heartbeat normal may be needed to treat arrhythmia.
  • pacemaker is a small device that doctors implant in the chest. An electrode attached to the pacemaker is placed in the heart wall, and small electrical impulses travel from a special battery through the wire to the heart, telling the heart when to beat.

  • defibrillator is similar to a pacemaker. It continuously monitors the heart for life-threatening rhythm problems. When it detects one, it sends an electrical shock to the heart to bring it back to a normal rhythm.

  • Sometimes, a child’s heart can become so weak that it needs more help than medicines can provide. In these cases, cardiac surgeons can connect the child’s heart to a mechanical pump that does the work of the heart. This kind of pump is called a VAD, and it can be placed inside or outside the body. VADs can support either the left or right ventricle or both. A VAD can be used for patients waiting for a heart transplant or for patients whose heart muscle needs time to rest and recover from an injury or infection.

    AJ’s Story

    When a virus attacked AJ’s heart, his team at Seattle Children’s recommended a ventricular assist device (VAD). The CentriMag pump allowed his heart to rest, heal and recover.

  • The heart transplant team at Seattle Children’s performs many transplants each year for children with cardiomyopathy or other heart problems that cannot be controlled using other treatments. Read more about our heart transplant program.

Contact Us 

Contact the Heart Center at 206-987-2515 to request an appointment, a second opinion or more information.

Providers, see how to refer a patient.