scar tissue

Hello everyone, 


I was just sat in my living room thinking about pacemakers and I had a thought. Scar tissue caused by myocardial infarction (heart attack) and scar tissue caused by cardiomyopathies can cause electrical impulses that cause potential dangerous arrhythmia. Does anyone know if this is the same as the scar tissue caused by pacemaker leads in the heart? 

If this is the case perhaps this could be a cause of some of my NSVT, or other pacemaker patients arrhythmia issues. I believe there could be a different type of scar tissue between these two scenarios, or I could be into something,

I hope someone has any ideas,

Thank you



I honestly don’t have an answer to your question.

by asully - 2021-07-03 02:56:34

I would think that any scar tissue in the heat could potentially cause electrical disturbance.  I know even inflammation or irritation of cardiomyocytes can trigger arrhythmias.  That is why they have a "blanking period" or "reset time" following an ablation.  All the fiddling around inside the heart can cause irritation and lead to arrhythmias, including NSVT.

In my own experience I had short runs of NSVT following my mitral valve replacement and again after my ablation.  The only other time I had them was due to a period of decompensation from stress induced cardiomyopathy (which as you know cardiomyopathy itself can stretch or stress the cells leading to arrhythmias.

I suppose my answer is it seems like a rational trigger for NSVT or other arrhythmias.  Whether it is truly known to cause trouble, or may be behind your struggles with NSVT I don't know.  If you don't find a satisfactory answer to your question DM me and I will be happy to see what I can dig up in medical literature!

By the way wanted to give you props, clever line of thinking!


I don't think that's right.

by crustyg - 2021-07-03 03:53:19

I think the basic idea/thought is incorrect.

Scar tissue does not cause electrical activations - there are no impulse generating cells in scar tissue, which is why replacement of previously healthy heart muscle with scar tissue after an aterial blockage often causes conduction difficulties (e.g. CHB after a large anterior infarct).

What often happens is that the disease process that can lead to the formation of scar tissue affects the electrically active cells, and as they hover between cell life and cell death they can fire off inappropriately, and that causes abnormal activations.  Scar tissue (fibrous cells) are alive and do have a cell potential, but their oxygen needs are much lower than the cells that they replace so they are effectively inert.  They don't contract (except very slowly to pull other cells together - useful for closing holes in skin etc.) and they don't take part in electrical activation or conduction of impulses.

So the scar tissue at the tip of your pacing leads does *not* create PVCs.  Remember that the vendor puts a tiny amount of a steroid at the tip of each pacing lead expressly to reduce the development of scar tissue between the pacing lead and heart muscle, but over time some scar tissue forms around the tip of the lead providing a secondary anchor.

Prodding heart tissue with a lead/wire can cause abnormal activations, so VT or even VF is a recognised complication of internal ablation, or pacing wire insertions but usually treated and stopped within seconds during the procedure.  The less healthy the heart muscle to start with, the more likely it is to have this type of problem.  The more that heart muscle is bathed in excess stress hormones the more likely it is to react with extra beats.  Brain => heart.


Scar tissue

by Gemita - 2021-07-03 05:50:12


Have you seen improvements in your symptoms following your PM upgrade to two leads or have you noticed a worsening of your palpitations, in particular your NSVT?  That would be my first question to you.

It is true that scar tissue can build over time around the PM lead tips that are attached to the heart tissue but this would be a build up of "isolated" tissue around the lead tips only, whereas from say a heart attack the scarring would be more extensive, depending on the patient, on the severity of the heart attack and on any other health condition the patient may have. I would say it is primarily the "condition" causing the heart attack which is the cause of an arrhythmia - say arterial blockages, heart failure - rather than the scarring alone.  So far you do not seem to have any major cause identified for your NSVT, neither scarring, nor a health condition.

I attach a link which might be worth a read Hayden about formation of scar tissue, so it is a whole new subject and a very complex one.  I do in fact have an inherited condition known as Ehlers Danlos syndrome, a connective tissue disorder and I am prone to excessive scarring, even from minor injuries.  However I have many other more common potential causes for my arrhythmias Hayden before I go down the Ehlers Danlos route.

Practically, my best advice would be to ask your doctors if you could have some imaging (1) to have a look for any new scarring of your heart tissue and if confirmed (2) to rule in or out auto immune condition Lupus as a possible cause for any arrhythmia since your mother had the condition, unless that has already been done?  In your case, a potential Lupus diagnosis would be my only concern for you Hayden. You could also ask your doctors (3) if this could possibly be a pacemaker mediated arrhythmia that could settle with some settings changes or with time?

My arrhythmias settled after months of worsening symptoms following pacemaker implant.  Some of us are just plain sensitive to any intervention Hayden.  I would not focus too much or worry about pacemaker lead tips creating scar tissue as a potential cause for your NSVT.  If imaging can rule out more extensive scarring of heart tissue as a potential cause for your NSVT, it might reassure you and answer your question Hayden?  But as I have said in the past, NSVT is very very common, even among healthy young athletes and as long as it stays non sustained and causes minimal symptoms, doctors are usually not too concerned.  A good question though Hayden and one for your caring doctors.

Thank you, interesting ideas

by PacerPrice - 2021-07-03 07:43:35

Thank you everyone for your replies, I am only 17 and have been convinced I want to be a doctor since i was around 4 so these strange medical thoughts often happen in my head! 

From what everyone has said I can see that there could be different types of "irritable" tissue and the scar tissue around the pacemaker lead could be almost deactivated. Crusty thank you for pointing out that the cells around the pacemaker wire wouldn't even bear really, i think this helps my understanding a lot. 

Asully, thank you for your help and you make a really good point that after a procedure short runs of arrhythmia can happen, probably due to healing i assume. 

Thank you Gemita, I have been feeling quite a bit better. although i do feel quite tired during exercise, even walking, sometimes. I think this could be down to the beta blocker i'm not too sure. I have just been transferred to Adult care last week, and I must say it is very different, the patient- doctor communication is a lot less and they only want to see me once a year. 

I think this caused a lot of added anxiety as the doctor didn't really seem to know what was going on with the NSVT or anything at great ormand street ( he was asking me everything that had happened to me like he didn't know, i hope he does!).  

You made some really interesting points and i will definitely look into the article you have sent. Thank you so much as always. 

I hope everyone is okay and thank you for your help! 

Adult care…

by asully - 2021-07-03 14:38:37

I'm not sure if you live in the states or not, but I think you will find the "adult care" is extremely lacking in any field.  Most doctors spend less than 10 min with you, and rarely do they take the time to give a good explanation.  I have a theory that this is due to the fact that they don't know how to break down complex topics into something any layman would understand.  If you tell your doctors to talk to you more like they would a colleague and tell them you will ask questions when you don't understand you might find you get more information out of them (this is what I do with my doctors).  Many of them appreciate not having to change the language they use and they can typically cover more stuff in a shorter period of time, however you will always find a few bad seeds who just don't want to talk.  Make sure you find a doctor you trust and get along with because in your case it is likely going to be a relationship you have for years or decades.

Thank you for the advice

by PacerPrice - 2021-07-03 16:25:35

Thank you asully, I will definitely ask them to speak to me like a colleague as I do feel the conversation is lacking a bit as they don't explain everything in depth. They will find out your fine and then that's that,


Thank you,



by Gemita - 2021-07-03 17:58:47

I think you would make a very compassionate doctor and spend a lot of time listening to your patients.  If it would be your dream, then start to make it happen.  Even if you didn’t reach your goal, you would learn a lot along the way, especially as you seem to love the subject and want to know more about yourself and your pacemaker.   

I am sorry you find Adult care rather disappointing after the excellent treatment you received at Great Ormond Street Hospital.   I can imagine how difficult it will be to adjust and I can only suggest that if you find it too difficult to settle with your current clinic or doctors, you are always free to find another doctor to work with, with perhaps a specialist understanding of your condition.  

I switched Cardiologist/EP in the same clinic/hospital by mutual agreement, so do not feel that you have to remain with a doctor you feel uncomfortable with, but give it time.  You might find in fairness to your current team, they sometimes want to hear directly from you what you feel about your condition, what your symptoms are, rather than reading from your notes and taking the lead.  You are no longer a Great Ormond Street Hospital child and your new team may be looking to you for guidance about your condition, and how this might impact on your life.  You are an equal partner in your care now and it will take some getting used to, but I have confidence you will do well.

Talk to your doctors if you eventually feel your beta blocker is holding you back and making exercise difficult for you.  Many of us find a beta blocker difficult to tolerate, so you are not alone.  There are several beta blockers you can try until you find one that suits, but the beta blocker will help you to stay calm and will also keep your anxiety levels down.

Remember we are always here if you need us. 

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