Many individuals with DCM experience no symptoms. For those who have heart failure symptoms, it may include the following:

Newborns and babies

• Difficulty feeding or poor growth
• Excessive sweating during feeds or activity
• Excessive fussiness
• Fast breathing

Older children and adults

• Shortness of breath and fatigue
• Feeling dizzy or light-headed
• Fainting or passing out (syncope)
• Persistent cough
• Feeling abnormal heart beats (palpitations)
• Unexplained weight gain or swelling

A family history of DCM is present in around 20 to 50 percent of cases. It is possible that parents, siblings and even aunts / uncles or cousins of an individual with DCM may also have a heart muscle condition.

The most common acquired cause of DCM in children is myocarditis, which is inflammation of the heart muscle that can be caused by a viral illness. These viruses are the same illnesses that may cause a common cold, but in some children leads to a heart muscle problem.

Other causes include:

• Chemotherapy exposure
• Metabolic diseases

In some cases, there is no known cause of DCM. This is often referred to as idiopathic cardiomyopathy.

The following are possible methods of diagnosing DCM:

• Medical history of heart failure symptoms including feeding issues, rhythm irregularities and exercise intolerance
• Physical exam to assess skeletal muscle strength and identify signs of possible cardiac problems
• Echocardiogram – noninvasive ultrasound test that uses sound waves to produce images of the heart
• Blood tests
• Electrocardiogram (EKG or ECG) - quick, painless and noninvasive test in which electrodes are taped to the chest to record the heart’s electrical signals
• Electrophysiologic (EP) testing – physicians insert catheters into the heart to record electrical activity and determine the cause of the rhythm disturbance
• Cardiac MRI (magnetic resonance imaging) - noninvasive medical test that uses magnetic field and radio wave energy to make detailed pictures of the heart’s internal structure
• Exercise stress echo test which involves exercising on a treadmill or stationary cycle under close monitoring
• Genetic Testing — to determine whether or not a genetic mutation is present
• Family history of cardiomyopathy, rhythm problems, sudden cardiac or unexplained death, cardiac surgery or presence of other cardiac disease in relatives.
• Myocardial biopsy – tiny instrument is inserted into the heart via a vessel in the leg to retrieve a tissue sample that will be examined for the cause of the child’s cardiomyopathy

Echocardiogram is the most common test used to diagnose DCM, as the expansion of the ventricle and overall squeeze of the heart can be measured.

It is recommended that all first-degree relatives of a child with DCM undergo a routine cardiac evaluation. This includes parents, brothers, sisters and children.

A genetic counselor and / or geneticist can assess the family history and provide information about the chances of a genetic predisposition to cardiomyopathy.

Please read more about genetic testing for cardiomyopathy.

Treatment of DCM is unique for every child, designed to address the root cause of the heart failure (if known). The primary goal is to improve heart function and prevent symptoms. Various methods of treatment may include:

• Medications to treat symptoms, reverse heart damage and prevent further damage to the heart muscle
• Lifestyle changes such as limiting activity if the child becomes tired, dizzy or has difficulty breathing – competitive sports may be discouraged
• Implantable cardioverter-defibrillator (ICD), an automated device placed under the skin that tracks the heart rate and sends electrical signals to the heart if it detects abnormalities
• Pacemaker (cardiac resynchronization therapy) – commonly combined with ICD treatment. It is a small device placed in the body to control heart rhythms

In serious cases of heart failure, the child may need the following:

• Berlin heart device – a mechanical device placed in the body to help the heart pump and supply blood throughout the body
• Heart transplant is considered for children with severe, life-threatening heart failure