Genetic Syndromes: Channelopathies & Cardiomyopathies

Heart muscle cells contract because of 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 thoughtful discussion with your healthcare team.

The genetic changes that cause some channelopathies may even guide your cardiologist or electrophysiologist (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.

Long QT syndrome (LQTS)

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

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 cardiomyopathies (ARVC)

Information Coming in November 2020

Dilated Cardiomyopathy

Information Coming in November 2020

Hypertrophic Cardiomyopathy

Information Coming in November 2020

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)

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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