Any know the cause of their heart block???

I know this had been asked a zillion times. I'm curious if anyone knows why they developed heart block. I developed 2:1 exercise induced high grade block at 46years old.  Ruled out sarcoidosis and Lyme.  No other explanation except meningitis I had 2 years prior or my many years of exercising and sports.




by AgentX86 - 2020-11-10 22:44:16

The only solid relationship I've seen between one's actions and the heart's electrical system is between endurance athletics and Afib.  Of course disease can cause structural damage, which can result in electrical problems but the structural problems should apparent.

From the other direction, why do you care what caused it?  You can't go back and do something different.  You're here.  Where you're going is far more important than where you were.

Possibly fibrosis

by crustyg - 2020-11-11 04:39:32

My EP-doc and I had this conversation about SA-node failure: his answer was that it's probably a fibrosis process - slowly, over time, the repetitive damage/injury to the heart of endurance athletics/sport results in a fibrosis process (scar tissue).

We know that sustained hard exrcise does *some* damage to the heart - you can demonstrate mildly raised cardiac troponin levels after a long run or cycle, we know that over time long distance runners damage their skeletal muscle (covered in Tim Noakes bible 'The Lore of Running') - and yes, cardiac muscle isn't the same as skeletal muscle, but all tissues have a balance between oxygen supply and oxygen demand, and the heart is particularly unfortunate that it can only receive its blood supply during disastole, so that balance easily tips into the negative at high HRs.

What does this tell us about the natural history of HB: actually not that much.  Most fibrosis processes stop when the insult is removed (but, sadly, not all).  Will HB progress to CHB? Depends on the degreee of HB.

Just remember that the commonest cause of HB is ischaemic heart disease - furred up coronary arteries - which you probably don't have, and be pleased that you've avoided that through your own efforts.


Inherited condition

by Gemita - 2020-11-11 05:12:18


I guess no one can pinpoint with 100% certainty what has caused/contributed to their heart block/electrical disturbances because so many factors may contribute to a failing electrical system, from plain wear and tear and old age, to infections, inflammation, scarring, ischaemic heart disease, lung disease, thyroid disease, diabetes, medication, electrolyte imbalances to exercise induced cardiomyopathy and so the list goes on.  I do not believe there can ever be only one cause.  

For me personally, my doctors are telling me that the most likely trigger for my heart’s electrical disturbances is an inherited condition known as Ehlers Danlos Syndrome - a connective tissue disorder - which has affected my autonomic nervous system causing problems with heart rate, blood pressure, swallowing, bowel/bladder function and body temperature regulation.  It can be difficult to live with.  It seems to be on my father’s side.  He died at a very early age from a massive stroke, probably due to atrial fibrillation.

But we are all still here to tell the story so the treatment must be working.  We are the fortunate ones.


A Drug--Armour Thyroid

by Swangirl - 2020-11-11 23:16:53

I got a lethal arhythmia from Armour Thyroid which an endocrinologist prescribed for hypothyroidism.  I ended up in the ER and my heart never regained it's normal rhythm progressing from stage 1 to a complete block


by doublehorn48 - 2020-11-12 11:00:20

I go along with AgentX86, it really doesn't matter.  When I went to the hospital because any exertion caused me to gasp for air, they ran a battery of tests.  I had had a viral infection and that messed up my electrical system.  I can do just about anything except run a 100 yard dash.

Thank you!

by PacedNRunning - 2020-11-12 14:57:36

You all have given great insight.  To answer AgentX, the reason I would like to have some idea of the cause is because I don't want to find out a year later something else was brewing in my body that could have been taken care of but we sadly ignored it.  I did have hyperthyroidism for any years untreated. My levels were very low but because I was asymptomatic, the doctors never treated me. They just kept asking if I had symptoms and I would get yearly thyroid tests. They kept waiting for me to lose weight and become tachycardic. Well since I was active, I was bradycardic and never experienced tachycardia.  I then suddenly lost 30lbs unintentionally in 3 mos.  I was then treated.  So my EP thinks this could also be a cause. The many years of being untreated for my thyroid. Because of that experience, it has changed the way I handle my health. When a doctor tells me I'm fine, carry on. I don't usually take this as answer any longer.  When I first started having heart symptoms, the first Cardio I saw told me I was fine and I wasn't going to die! His words to my Zio results.  He basically said it's great news! You're not going to die.  I never thought I was going to die? Such a weird answer to start the results with my zio with. Even after I explained to him, I felt my heart rate slow down while running. He brushed if off as normal.  Needless to say I got a second opinion because I knew that crap wasn't normal.  I have read the book "the haywired heart". Very good read. I don't compare to any of those athletes in the book. I have been playing sports since I was 14, into college and beyond. Not at the same intensity but I guess 32 years of being active can do that.  I just wanted to make sure it wasn't something else crazy going on we don't know about.  

Fibrosis is a very common reason but again at 46 years old? Usually this develops much older. I am very thankful for my pacemaker. I wouldn't be the same without it.  I know a lot of us will never know the cause.  


thank you for all your answers!! Very appreciated



My SA-node failure started in my 50s

by crustyg - 2020-11-12 15:35:24

I disagree.  You can do serious damage to muscle by the time you get to your 40s - and your heart is just as susceptible to damage as your skeletal muscles.

I think that there's a very good chance that the early developers of exercise-induced arrhythmias will turn out to have one or more gene defects.  The whole body of knowledge around E-D seems to change yearly, as reluctant docs send off samples for analysis and the labs identify previously unknown genotype defects in the recognised collagen genes (and related ones).  The idea that you need 2-3 generations of ruptured aortic aneurysms in 20-40year olds in your family tree before you qualify for gene sequencing is about 25years out of date, IMHO.

Tim Noakes has examples of lifelong athletes in their 40s being outpaced by new runners in their early 50s precisely because the older runners don't have damaged, fibrosed muscles.

Yes, at 46 years old

by AgentX86 - 2020-11-12 17:47:55

Thirty is not too early for distance runners to show the effects of fibrosis.  It's a well known problem with any endurance sports.  Runners, in particular, have a very high instance of Afib, for instance.

If you insist on looking backwards, you'll never see where you're going.

But I’ve only been a runner 10 years

by PacedNRunning - 2020-11-13 05:02:25

I've been running about 10 years. Never completed a marathon. Only did 3 half marathons. I mainly did 10k's. even my doctor agreed my activity level didn't match my heart rate. I don't have sinus node dysfunction, I have AV block. I predominantly played volleyball in my adult life. Didn't do any sports for about 5-6 years. So for me, I question the endurance thing. It's not really looking  backwards, it's called learning from past mistakes. I've been misdiagnosed a few times! Doctors take one look at me and say "your fine!"  Your young and healthy. Meningitis, almost died. Saw 2 doctors. One said sinus infection for my horrible headache and another doctor straight up said don't know what's wrong with you. Crawled into the ER days later and amazingly they knew almost immediately what was wrong. Same with pneumonia. Told the doctor I could barely breath walking to the bathroom. She brushed me off. Told her I'm a runner and if I'm telling you I can't breathe, I can't breath. She rolled her eyes. After the chest X-ray she was blowing up my phone to come back. So I'm sorry but my medical history and the trust in doctors looking at you and judging you based on how you look makes me not always trust Their treatment. When I was worked Up for sarcoidosis as a cause to my heart block. I found out through messages boards a CT scan is not good enough to rule it out. I needed a PET SCAN. That scared the crap out of me because had no one told me, I wouldn't  have known. Sarcoidosis can kill you if not treated when it affects the heart. So no, I don't always trust medical people and I'm a nurse! It's always best be to an advocate for your health and knowledgeable. You can't totally trust them 100% because not everyone is perfect. 
I'm just curious more now because my heart block is now CHB from intermittent. My doctor thought I would barely pace and it would never progress worse. Well here I am 100% V paced and obviously it's worse. So makes me wonder did we miss something? I personally know HB doesn't get better But worse. I think when I asked my doctor prior to my PM, he didn't understand my question. Because now he says he expected it to get worse just not this soon. 

I know the answer is always no one really knows but I was curious of new answers. Appreciate your response but understand I'm now dwelling in the past. I'm trying to move forward in my brain because relying on something for the rest of your life to function daily fucks your mind. :) 

Dwelling in the past ? Absolutely not !!

by Gemita - 2020-11-13 12:24:19


You are not dwelling in the past.  You are very much addressing the present and paving the way for a better future and who can blame you for that.  What extra we can learn about ourselves today, will help us to manage our future and hopefully to halt any further deterioration in our condition.  It is human nature to try to protect ourselves and only we can do this.  If we totally relied on our doctors, we would be lost and all the poorer.  

I think we have all learned something from this thread and thank you for posting.  I know there is far more to my health problems than is apparent and I will never give up the search to find a better way to live my life, to improve my health, so that I can make the most of what time I have left.

I wish you a safe journey too and let's keep asking each other questions.  It really does help clarify our thoughts

Dwelling in the past

by AgentX86 - 2020-11-14 00:11:07

You're probably right.  At that level, it's unlikey that your sports have contributed to you relectrical problems.  The point is that this is the only known direct cause of AF and other electrical problems. If this didn't cause your problems, dwelling on why is even less useful.  We can't know why and it really doesn't matter because we can't go back. We can spend a lot of counterproductive time beating ourselves up.


by PacedNRunning - 2020-11-15 03:42:09

Thank you!!!  My first year after my AV block diagonals, I felt ok not knowing the cause because I know it's hard to know the exactly cause.  but with the recent complete HB, I'm back to asking myself, is all ok?  Should we make sure one more time something is brewing.  I'm sure this is normal with our health. We probably go back and forth with how we content we feel.  Thank you.  I hope you find answers.




by PacedNRunning - 2020-11-15 03:46:02

I honestly think this is the difference between men and women. Men get over things quicker than women. I know my husband does.  I might get mad about something and talk about it for 5 more minutes.  He's already moved on.  Our brains are just different.  Trust me, I wont' be searching long for a cause. Just like when I was first diagnosed. We tried ruling out reversible causes etc and then moved onto surgery.  Just wanted to make another round around a possible cause since it got worse.  




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