Genetic Testing

Has anyone here had genetic testing for heart block? I finally had my appointment with the inherited cardiac conditions team today (1 year later than it should thanks to covid) and they want to carry out genetic testing, despite it potentially being non-beneficial.

I am wondering what genes can cause heart block?


11 Comments

Not had mine yet

by quikjraw - 2021-04-08 11:24:52

I also am planned in for the genetic test Savannah but still waiting for the appointment. I also have heart block.

I do not know yet what they would do with the results. I assume my children would be tested?

 

 

Heart block

by Tracey_E - 2021-04-08 12:10:02

Is your heart block congenital? Acquired is different.

From everything I've read, the only genetic link with congenital heart block is moms with Lupus have a higher chance of giving birth to a child with heart block. Otherwise, it's just a fluke. I have not bothered with genetic testing and my kids have not either. When they were 10 or so, my cardiologist did a quick work up on both of them, but it was mostly for his curiosity, not because we expected to find anything. I've always been told that mine is random, and that my kids have no more chance of getting it than I did. 

There are other heart issues which are genetic and genetic testing is appropriate. IMO, heart block is not one of them.

Genetic testing requires your consent

by crustyg - 2021-04-08 17:20:50

In most jurisdictions, genetic testing requires your consent - especially as it may be 'non-beneficial' to use your phrase.

I'm not an expert in this field, but I agree with Tracey that I'm not aware of any genes considered to be likely to cause HB.

There is a lot of interest in whole exome sequencing (WES) to look for candidate genes for conditions for which we don't currently have identified gene defects causing disease: typically this requires two family members to be really helpful.  The whole field of genetic analysis using next-generation techniques is exploding, helping to unpick some clinical conundrums, and, in many cases, providing much better genetic advice for those considering having children.  Unfortunately WES also throws up lots of Variants of Unknown Significance (VUS), which are exactly what they say: genes or parts of genes that are different to the consensus 'normal genes' but which have no proven role in causing disease - yet.  In the UK, when applying for any form of life insurance, you *must* answer truthfully the 'Have you had any genetic testing' question.  Otherwise the policy is invalid.

In Germany, after their experience of eugenics some years ago, it's illegal for life insurance companies to even ask that question.

Back to you: you need to be convinced that genetic analysis is worth the potential issues later (life-insurance, mortgage protection etc.), versus the benefits that may be derived by someone else.  Otherwise you keep saying NO, even if it's just for a Research study.

It's that simple.

[Added later] A decent genetics lab using NGS (+/- Sanger sequencing for confirmation) will take about a month to produce results.  Two, if they start with a gene panel and then go on to WES.

Genetic testing should *always* be done if there's a family history of sudden cardiac death.  There are genes that cause this - famously Long-QT syndrome, which couldn't be diagnosed post-mortem back in the 1980s - and plenty of others now.  Acquired CHB can present as sudden cardiac death, but that's not the usual way.

Terminology?

by Persephone - 2021-04-08 18:33:03

This is an interesting discussion.  I noticed that my doc started using the term "congenital" in my medical reports about 1.5 years after my initial diagnosis of 2-3 degree HB requiring PM implant at age 55. The doc required me to be transported to the emergency room after a stress test revealed the HB.  Other than a Lyme disease test that was done there (and boy, was the surgeon worked up that waiting for those results pushed the surgery into a late Friday afternoon), there was no determination of the origin.  This was just my experience.

Mine is in process

by Tulp - 2021-04-08 22:40:41

I had a test done in November when I was first diagnosed.

I had  a left block and serious heart failure (a dilated left ventricule). No real explanation nor appaent reasons. They warned me that it would ttake about a year toget the results.

Persephone

by Tracey_E - 2021-04-09 09:14:49

Once heart block is diagnosed, it's common to not bother looking further because 1) it doesn't change anything and 2) it's rare to get any answers no matter how much testing they do

Testing and HB

by Persephone - 2021-04-09 13:26:37

Thanks Tracey - I've understood this to be the case, though it took some time to get past the initial "wondering why" stage.  I'm just a bit confused about the terms congenital vs. acquired... if the Lyme test had come back postive, for example, would the HB have been called acquired?  Or is the term acquired reserved for HB caused by medical procedures?

I can understand why people may think it appropriate to seek genetic testing if they get a label of congenital HB rather than "of unknown origin"

Genetic testing

by AgentX86 - 2021-04-09 14:53:08

I really don't see why anyone would care about the "why", unless the information is going to be used in the decision to have children.  That's a little extreme, IMO.

Benefits of Genetic Testing

by JayKay - 2021-04-10 11:05:53

After a sudden unexplained syncope episode, I went to the ER. They monitored me for a few hours and said I had heart block. The attending physician also said I should see a cardiologist due to family history of sudden death at 40. Shortly after, I had an echocardiogram and wore a monitor for two weeks. Results from both of these came back normal. 
One month after that initial diagnosis of heart block, I experienced 19 episodes of recurrent Torsades while in the hospital. Two were self terminating. I was cardioverted out of the other 17. 
The electrophysiologist on staff said it was probably congenital Long QT Type 3 or Brugada. 


An ICD was implanted and medication was prescribed. When figuring out medication options, the EP said there are lots of beta-blockers on the market, but most shouldn't be used if you have one of these congenital variants. Unfortunately, these two beta-blockers don't have the best reputation for being well tolerated and are prescribed as more of a last resort.


Then there's the benefit of knowing for family planning reasons, and it will be much less expensive for your relatives to figure out if they are at risk. They can get tested for one gene as opposed to an entire cardiac panel.

In summary:

1. Are you sure you have heart block or could it be something else?

2. If you think you might have something else, would the treatment plan change? Would some basic over the counter medications be contraindicated?

3. Are other family members concerned about their own well-being, and risk of sudden death? Would having a diagnosis change how they seek care?

acquired vs congenital

by Tracey_E - 2021-04-10 14:07:53

Congenital means we are born with it. Acquired means we got it later, by whatever means. It could be from Lyme, surgery, medication, infection or no known reason.  Unless you are on an ekg while in block, it's possible to go years without diagnosing heart block, so sometimes they will call it congenital even though it wasn't diagnosed until adulthood. 

Congenital is not the same thing as genetic. Genetic means there is something in our genes that caused it. Congenital heart block is not genetic, it's just being born without that electrical connection. It's nothing we inherited and we can't pass it on.

Thank you for the explanation

by Persephone - 2021-04-10 15:28:11

Thank you, Tracey - your explanation helps broaden my perspective.

You know you're wired when...

You have rhythm.

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A properly implanted and adjusted pacemaker will not even be noticeable after you get over the surgery.