Heart and Stroke Foundation researcher Dr. Andrew Krahn talking with patient

Using genetics to stop a killer

Cardiac arrest can strike without warning. Dr. Andrew Krahn is determined to change that.

It’s a tragic news story that often makes headlines — a young, healthy, fit athlete suddenly collapses and dies of cardiac arrest.

“Stricken in the prime of life” — that’s how Heart and Stroke Foundation researcher Dr. Andrew Krahn describes the five out of every 10,000 Canadians who suffer from long Q-T syndrome (LQTS).

This rare, often genetic condition puts perfectly healthy men, women and children at risk of a sudden cardiac arrest — and death.

Imagine if you had LQTS but didn’t know it. Or imagine if your child had LQTS, which Dr. Krahn calls the “lightning strike” of arrhythmia.

Either scenario is frightening. That’s why Dr. Krahn is working to develop an effective testing method for this and other inherited abnormalities. He is also in charge of a national registry of patients who experience unexplained cardiac arrest.

For every individual identified with arrhythmia, four more at-risk family members or relatives with the gene mutation can be identified, treated and potentially saved from dying from a sudden cardiac arrest.

Family members found to be at risk can then be given preventive treatments such as beta blocker pills or implantable defibrillators.

By studying these patients, Dr. Krahn is also hoping to uncover the DNA sequences responsible for the abnormalities, which can be used in diagnosis and risk prediction.

The aim is to better understand inherited electrical abnormalities, detect these conditions in vulnerable family members and protect them from sudden death.

  • Family history can double your risk of heart disease and stroke. Know your risk.

10 Responses

  1. Pingback : THE HSF BLOG Mother and son share a genetic risk

  2. SheriC

    Hi my name is Sheri, I am a 42 year old single mom of two toddlers and in May of this year I had a third degree complete heart block with no pulse for 22 seconds after pleading to see a cardiologist, then they read it as a normal 48 hour holter monitor result… I kept pushing for answers and to get back in to see the cardiologist… They begrudgingly let me come back for a consult… He (for the first time looked at the actual ecg) and I told them I had fainted… Woke up to my toddler crying in his room (I was pretty banged up) … He said I had no pulse for 22 seconds. The heart specialist hospital for our region have me an appointment date for 2 1/2 months later. I ended up not waiting because I was now sleep up to sleep… And if I stood for more than a few minutes I felt faint… Weak, nauseous, pulse was 40 and BP was 88/48 … Finally they admitted me to investigate… They said deal with my stress and it was a Vado vagal response and were sending me home as a single mom of two toddlers and said I was fine to drive… Just remain in the slow lanes in case I had to pull over! The electro physiologist was off the day I was to be discharged… Another Dr. Came on and said I needed a pacemaker… I got one the following week. The day I got out of hospital my 50 year old cousin with no previous heart issues was taken to hospital with a third degree heart block no pulse… They sent him home with a halter monitor for 48 hours and said he’s fine. He did not fight for answers even knowing what happened to me… I’m told to eat lots of salt, lots of h20 (but not so much I get rid of the salt (how to measure this I have no idea) my pace maker is working almost 50% of the time already… I have another cousin with fainting episodes, another with a pulse in the 30s (he was told until he starts fainting they will not do anything!). My daughter was born with a hole in her heart, my mom has had cardiac ablation surgery and my dad died of mismanaged aFib that caused two strokes – one he fully recovered from due to being given APT… Was not given an anti coagulant, cardiologist or neurologist… Was told just to get his BP checked every week or so from his GP! He died three months later due to a massive stroke…. My whole family is at serious risk… To me it looks like the very rare Familial Progressive Complete Heart Block… When I asked for genetic testing especially for my kids (age 2and 3) and my brother I was told genetic testing is inaccurate and my kids are fine right now. Seriously that is NOT AT ALL COMFORTING! PLEASE PLEASE SOMEONE HELP US! Don’t let even more needless tragedy take my kids or other loved ones… Please help I’m scared

    1. Sharon Hollingsworth

      Dear Sheri,
      Thank you for sharing your story on the Heart and Stroke Foundation’s blog. First of all, we are very sorry to learn of your heart issues and understand your frustration and stress caused by these events. The best advice we can offer you is to seek out a specialist who will look at your medical history and case overall. There is an online resource for genetic counsellors that includes Canada so this may be a helpful starting point for you to get some answers: http://nsgc.org/p/cm/ld/fid=164 In general, cardiovascular genetics testing is not well advanced but there is some testing for arrhythmias. We trust the information provided here may provide at least some measure of assistance. Yours in better health, Sharon at the Heart and Stroke Foundation

  3. K

    Are there any new genetic tests available yet for Long QT? I am diagnosed with Long QT 2 based on cardiac arrest and events surrounding it. But the genetic testing done 3 years ago does not confirm this diagnosis.

    1. Sharon Hollingsworth

      Good morning,

      Thank you for your comment on the Heart and Stroke Foundation blog. We appreciate it when readers participate in these online conversations.

      We’re sorry to hear about your experience and diagnosis with Long QT Syndrome. To respond to your comment about genetic testing, it’s important to remember that at this point, genetic testing is not the same as a diagnosis. The genetic screening you had done was looking for abnormal genes that could increase your risk but a positive result would not necessarily have meant that you would develop the disease. As I’m sure you know, LQTS is generally diagnosed by means of an ECG.

      If you’re worried that someone in your family may have the same disorder, I would suggest that you speak to your physician about a referral to a cardiologist who specializes in rhythm disorders.

      Thanks again for reaching out and I sincerely hope they you are now doing better following your diagnosis.

      Sincerely,
      Sharon at the Heart and Stroke Foundation

  4. I need the specialist for my heart ! I didn’t feel well and nobody helps me at all , many times to the hospital and they say I’m ok ! But I’m not , my name is Laura Bond and I have several missing beats , please

    1. Sharon Hollingsworth

      Hi Laura,
      I’m so sorry that you are experiencing what I am sure are very disturbing symptoms. The Heart and Stroke Foundation provides general health information to Canadians to help them live healthy lives and reduce their risk for heart disease and stroke. However we are unable to provide medical advice. While I understand you have already undergone medical care in hospital I would still suggest that you ask your family doctor to refer you to a cardiologist who can try to get to the bottom of your symptoms, and perhaps just as importantly, put your mind at rest.

      Thank you for reaching out to share your concerns, Laura. Best wishes for healthier days ahead.

      Sincerely,
      Sharon at the Heart and Stroke Foundation

  5. Mio

    Hi dear Heart And Stroke blog,

    I am just wondering if there any possibility to see Dr. Krahn for a consultation? I have prolonged QTc >500 ms during/after exercises (confirmed by tests), had few faints with injures (during sport activities) and a family history of sudden death from cardiac arrest before 50 y.o. My closest relatives suddenly died 20+ y.o., 42 and 49 y.o. I live in the rural area, and my doctors are not sure about the possible treatment. I have three kids and am very concerned about their future too.

    Thank you for this great opportunity to get some useful information from this wonderful blog.

    All the best,
    Mio.

    1. Sharon Hollingsworth

      Good morning Mio, and thank your for your kind comments regarding the Heart and Stroke Foundation blog. We are always delighted to hear from our readers and know that they are finding the content informative and helpful!

      Unfortunately we are unable to connect patients with Dr. Krahn for consultations. However I do understand your concerns in light of your family history so I suggest that you ask your family doctor for a referral to a specialist in heart rhythm disorders. While this may mean travel to a larger center for the appointment, I think it would be well worth the time and trouble to have your condition investigated and get some answers about the likelihood of your children inheriting your heart problems.

      Thanks again for reaching out, Mio. And best of luck in following up on this with your healthcare provider.

      Sincerely,
      Sharon at the Heart and Stroke Foundation

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