Genetic Syndromes in Children: Channelopathies & Cardiomyopathies

Heart muscle cells contract because of the movement of certain molecules (called "ions") across the walls (called "membranes") of the cells. Channelopathies increase a child's risk for life-threatening heart rhythms and for sudden cardiac death (SCD). It is important to remember that while channelopathies are serious medical conditions, they are frequently treatable when they are detected and properly diagnosed.

Cardiac genetic testing and genetic counseling can be valuable tools when evaluating patients, and their family members, for channelopathies.  

While cardiac (heart) genetic testing is valuable in both diagnosis and prognosis, it has limitations as well. Sometimes, a genetic change may be found that has not been shown to be disease-causing but also has not been found to be harmless. In addition, a genetic heart defect may be present but it is not able to be detected with current testing. Genetic testing is expensive, especially during the initial evaluation, because many genes may need to be tested.  These costs may or may not be covered by a patient’s medical insurance.  Finally, testing may take weeks to months to complete, and this waiting period can be very stressful for patients and their families.

Genetic testing and genetic counseling can be valuable tools when evaluating patients, and their family members, for channelopathies. 

The decision about whether or not to do cardiac genetic testing is best made after a thoughtful discussion with your healthcare team.

The genetic changes that cause some channelopathies may even guide your cardiologist or electrophysiologist (a cardiologist who specializes in heart rhythm conditions) to choose one specific medication. If a known disease-causing genetic mutation (change in the gene’s sequence or pattern) is found in a patient, it can help direct future testing in other family members to determine their risk of developing the disease.

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Long QT syndrome (LQTS) in Children

Long QT syndrome (LQTS) is a condition that affects the flow of ions into and out of the cells in the heart. This abnormal flow of ions can prolong the patient’s QT interval, which is measured on an ECG.  The prolonged QT interval affects how electrical impulses travel through the heart.  Electrical activity may be transmitted abnormally through the lower heart chambers (ventricles) leading to potentially life-threatening ventricular arrhythmias. LQT syndrome is usually, but not always, inherited.

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Brugada Syndrome (BrS) in Children

Brugada syndrome (BrS) is a channelopathy that can also cause dangerous ventricular arrhythmias. Patients with BrS can have an abnormal pattern on their ECG. Brugada syndrome is the rarest of the channelopathies and usually presents when a person is in their 30's to 40's.

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Arrhythmogenic Cardiomyopathy (AVC) in Children

Arrhythmogenic ventricular cardiomyopathy (AVC) is a rare condition that affects the heart muscle and can be associated with ventricular arrhythmias. Other names that are used interchangeably are arrhythmogenic right ventricular cardiomyopathy (ARVC), or arrhythmogenic right ventricular dysplasia (ARVD).

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Dilated Cardiomyopathy (DCM) in Children

Dilated cardiomyopathy (DCM) is a disease of the heart muscle. In dilated cardiomyopathy, the bottom chamber (left ventricle) of the heart becomes enlarged (dilated), thinning the walls of the ventricle, reducing the ability for the heart to squeeze effectively and pump blood efficiently.

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Hypertrophic Cardiomyopathy (HCM) in Children

Hypertrophic cardiomyopathy (HCM) is one of the most common heritable cardiac conditions and is the most common cause of sudden cardiac arrest in the young, affecting about 1 in 500 people. Familial HCM is a heart condition characterized by thickening (hypertrophy) of the heart muscle, more specifically the ventricle. The thickened heart muscle can make it challenging to keep up with the oxygen demands of the body and of the heart muscle itself.

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Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) in Children

CPVT is an abnormal heart rhythm (arrhythmia) caused by the body’s “fight or flight” response that happens in times of stress or physical exercise/exertion.  At these times, the body releases hormones called “catecholamines”, more commonly known as adrenaline, noradrenaline, and dopamine.

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Left Ventricular Non-Compaction (LVNC) in Children

Left ventricular non-compaction (LVNC) is a disease where the left ventricular muscle on the echocardiogram appears soft and spongy, instead of looking smooth and compact. 

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Restrictive Cardiomyopathy in Children

Restrictive Cardiomyopathy (RCM) is a rare disease where the heart muscle becomes rigid or stiff. This makes it difficult for the ventricles to relax and properly fill with blood.

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Heart Rhythm Disorders
Millions of people experience irregular or abnormal heartbeats, called arrhythmias, at some point in their lives. Most of the time, they are harmless and happen in healthy people free of heart disease. However, some abnormal heart rhythms can be serious or even deadly. Having other types of heart disease can also increase the risk of arrhythmias.
Pediatrics and Congenital Heart Disease (CHD)
This section is for pediatric patients and families living with heart rhythm disorders and heart rhythm disorders related to congenital heart disease (CHD).
Early Warning Signs
If you are experiencing a racing, pounding, rumbling or flopping feeling in your chest or if you have been fainting, having repeated dizzy spells, feeling lightheaded or you are extremely fatigued, it's time to see a doctor to discuss your heart health.
Common Treatments
Learning about the underlying cause of any heart rhythm disorder provides the basis for selecting the best treatment plan. Information and knowledge about care options, and their risks and benefits help you work with your health care provider to make the best choices.
Since other heart disorders increase the risk of developing abnormal heart rhythms, lifestyle changes often are recommended. Living a “heart healthy” lifestyle can ease the symptoms experienced with heart rhythm disorders and other heart disorders, and can be beneficial to overall patient health.
The Normal Heart
The heart is a fist-sized muscle that pumps blood through the body 24 hours a day, 365 days a year, without rest. The normal heart is made up of four parts: two atria on the top of the heart (right atrium and left atrium), and two ventricles (right ventricle and left ventricle) which are the muscular chambers on the bottom of the heart that provide the major power to pump blood.