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Inherited Heart Rhythm Conditions

Genetics FAQ

In this section you will find answers to some of the frequently asked questions regarding genetics.

A: Genetic testing is done by a simple blood draw. Genetic testing is an important, personal decision. It’s important for you and your family to understand exactly what genetic testing can and cannot tell you. Your genetic counsellor can go over this information in more detail during your appointment.

Genetic testing is a way to look for changes (such as a typo or spelling mistake) in a specific set of genes (eg. those involved in the heart’s electrical system).

A: Genetic counsellors are health professionals with specialized training and experience in the areas of medical genetics and counselling. Genetic counsellors work as members of a healthcare team, providing individuals and families with information on the nature, inheritance, and implications of genetic disorders to help them make informed medical and personal decisions.

A: You have two copies of each gene. One copy is from your mother and one copy is from your father. Most IHRCs are inherited in an autosomal dominant way which means that only one copy of the gene needs to have a change in order for the gene to not work properly. Someone with an IHRC has a 50% chance of passing on the gene with the variant to their child in each pregnancy. Both males and females can inherit the gene variant and be at risk.

A: A referral from your family doctor or a health care provider is needed to be seen in a Heart Rhythm Clinic. You may want to contact the Heart Rhythm Clinic directly for their referral information as requirements may differ across regions and provinces.

Below are examples of who should be referred:

• Patients with a suspected or known diagnosis of an inhertied heart rhythm condition
• Patients with a history of an unexplained sudden cardiac arrest
• Patients with a family history of an inhertied heart rhythm condition
• Parents with a family history of sudden unexplained death or sudden infant death syndrome

A: If you are concerned about your family history of a heart condition or sudden death, speak to your family doctor and consider the following questions:

• Has the diagnosis been confirmed by a heart specialist? Did your relative have genetic testing? Is a copy of the genetic testing report available?
• Was a cause of death found? Was an autopsy performed? Is a copy of the autopsy report available?
• What are the circumstances behind the death? (ie. Were they asleep, exercising, swimming, just resting?) How old was your relative?

Your family doctor can help with a referral or you can call your local heart rhythm clinic to discuss the family history you are worried about.

A: Results can differ depending on your situation. If you have a known diagnosis of an inherited heart rhythm condition (IHRC), then you were probably offered a broad panel test. The possible results are:

1. Positive Result

A positive result means that a disease-causing or pathogenic gene change was found. Disease-causing or pathogenic are gene variants that are known to cause a specific disease or heart condition. Disease-causing or pathogenic variants have been seen in other people with your heart condition and they are known to affect the heart muscle and/or heart beat. The genetic explanation for your heart condition has been found.

What does this mean for me?

Knowing whether you carry a specific gene variant can sometimes help doctors decide which treatment is best for you.

What does this mean for my family?

A positive result means that a disease-causing or pathogenic gene change was found. Disease-causing or pathogenic are gene variants that have been seen in other people and are known to cause a specific disease or heart condition. The genetic explanation for your heart condition has been found.

2. Negative Result

No changes in the tested genes were found.

What does this mean for me?

We have not yet found the genetic cause for your heart condition. This is because the test isn’t perfect and the variant might be in a gene or in a part of the gene that was not tested. This result does not change your medical treatment. Your heart condition could still have a genetic cause.

What does this mean for my family?

Because we have not found the genetic cause of your heart condition, we can’t offer genetic testing to your family members. Because your heart condition may still be genetic, we recommend that close family members have heart tests which would be reviewed by a heart rhythm specialist.

3. Inconclusive Result or Variant of Unknown Significance

A gene change was found, but not enough information is available to tell us whether or not it is causing your heart condition. Sometimes genetic testing finds a gene variant that has never been seen before, or that is not well understood. This type of gene variant is called a “variant of unknown significance (VUS)”.

What does this mean for me?

Additional genetic testing may be considered, now or in the future. This result does not change your medical treatment. Your heart condition could still have a genetic cause.

What does this mean for my family?

Because we have not found the genetic cause of your heart condition, we can’t offer genetic testing to your family members. Because your heart condition may still be genetic, we recommend that close family members have heart tests which would be reviewed by a heart rhythm specialist.

If you have a family history of an IHRC and a disease causing variant was found, you were probably offered targeted familial testing. There are two possible results:

1. Positive Result:

This confirms that you have inherited the gene variant causing the condition in your family. You have an increased chance to develop the signs and symptoms of this condition. Ongoing follow up with a heart rhythm specialist is recommended. You may be offered preventative treatment and/or lifestyle advice. Each of your children have a 50% chance of inheriting this variant from you. Genetic testing is available to them.

2. Negative Result

This confirms that you did not inherit the gene variant causing the condition in your family. You are not at increased risk to develop the signs and symptoms of this condition based on this family history. You can still develop heart problems that are common in the general population. No ongoing follow up with a heart rhythm specialist is required. Your children are not at risk of inheriting this genetic variant from you.

A:Your genetic counsellor can review the possible implications of your test results with you. Please keep in mind that every insurance policy/company is different and may handle genetic test results differently. Additional information can be found at:

A: Approval must be obtained from the Medical Service Plan which can take up to 3 months. Once approval is obtained, it will take approximately 1-2 months to receive the results of this test. Your genetic counselor will call you with the results as soon as they are available.

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