Falling Ejection Fraction - Is it Pacemaker Induced?

Hi All

I am new to the club but have been watching from afar for a while now.  You have been a fantastic help to me over recent months and are all incredibly generous with your time and the contributions you make to help people.  It's always better to feel you are not on your own with this and it's taking me some time to accept my new wired status.

I had a dual chamber pacemaker fitted back in February 2021 after becoming extremely bradycardic and subsequently being diagnosed with AV node block.  After some initial recovery I started to go downhill again and while I can function I am really struggling with exercise and anything which works the heart a bit more (climbing stairs, hills etc).  This has had a major impact on my life as I previously loved taking long walks and hiking in the Welsh hills. My energy levels are very much lower, particularly in the morning.  My hubby has has to be roped in for the school run as there is no way I could get up and out with the kids which I wouldn't have thought twice about before.

I have had an exercise stress test which showed that my ejection fraction has dropped to 45% (it was around 60% prior to surgery) and septal hypokinesis which becomes more exaggerated with exercise.  My cardiologist seems to be taking a wait and see approach to my treatment but I'm not sure if this is the best strategy.  I have spoken to a private cardiologist who agreed with my theory that I may have pacemaker induced cardiomyopathy. I am 100% paced and this can be linked to left ventricular issues for some people. My options would be upgrade to a biventricular device or left bundle pacing (the second option is not widely available here so I would probably need to go private if I could afford it).  

Has anyone else had a  pacemaker induced fall in ejection fraction and how have you approached it?  Also, have any members had left bundle pacing and how successful has it been for them?  Any advice would be much appreciated.  



Nice start, knowledge is power

by Terry - 2022-05-22 18:33:01

Left bundle or His bundle. See how left bundle branch pacing compares in studies listed on the Papers page of <www.His-pacing.org>. Perhaps we can find you an expert. Know that there are studies that conclude that with natural physiological ventricular pacing, your heart can heal "pacing induced cardiomyopathy."


I would wait and seek a third opinion

by Gemita - 2022-05-22 21:03:47

Hello Seenbetterdays, I know the feeling!

Firstly welcome and thank you for your kind words to us all.  I am so sorry to hear of your difficulties and concerns that your pacemaker may have caused a fall in your ejection fraction.  Of course this is by no means a certainty and it might be helpful not to rush into anything until you are clearer about what you are dealing with and the cause?  An ejection fraction of 45% is not critically low and could well bounce back to a healthier level at the next echo testing, say in three months time, since ejection fraction can change in response to other health conditions, to changes in medication, to blood pressure, to a higher heart rate and so on.  If at that time it is clear that your ejection fraction hasn’t recovered, you could then with confidence pursue other possibilities.  I note your septal hypokinesis (decreased heart wall motion).

Although many of us are well aware of the potential dangers of right ventricular pacing, it certainly doesn’t happen to the majority of patients who are 100% paced in the right ventricle.  According to my EP if it is going to happen, it will happen quickly (during the first 3 months to a year) and if it doesn’t happen during this time, it probably never will.  There are many members here with AV Block who have been paced in the right ventricle since childhood and who have never developed signs of pacemaker induced cardiomyopathy.

I do understand you are having difficulties with your activities, but whether you should go rushing in to having another surgery when you are not really sure whether your Ejection Fraction has permanently dropped, would worry me.  Our NICE guidelines I believe suggest 35% or less EF is the indication for CRT although individual circumstances will be taken into account.  I wonder if it would be wise to seek an opinion from another NHS hospital consultant, one with experience with CRT and/or HIS bundle pacing, even if this means travelling to find an experienced surgeon?  They might also try to make adjustments to your current pacemaker settings first to see if that would make a difference before having a pacemaker upgrade and having to face another procedure so soon?

There are members here who have HIS bundle pacing and I hope they will respond.  I wish you well.

Attach a few links I found very helpful on HIS Bundle

by Gemita - 2022-05-23 06:30:21

1. Pacemaker Club link where a member had a successful HIS bundle experience

2.  British Journal of Cardiology link on HIS bundle pacing

3.  ahajournals.org link (full info on HIS bundle pacing, including potential disadvantages).

You need to copy and paste these into your main browser to open.  Links will not open on clicking!




Thank You

by SeenBetterDays - 2022-05-23 06:38:30

Thank you so much for taking the time to respond.  I think I have so many unknowns it is very difficult to make a decision.  I have been told that left bundle pacing is easier to achieve than HIS pacing so just wondered if anyone had experience of that type of surgery in the UK.  You may be right that I am jumping the gun, I think I am just scared of leaving it too late when I could have intervened and maybe turned things around.  I have two teenagers and I am desperate to be there and watch how their lives develop.

It is natural to worry . . .

by Gemita - 2022-05-23 07:28:38

I would be just the same in your shoes, but sometimes waiting and watching can be effective and kinder on your body than rushing in too early without knowing the full story.  Waiting may uncover more information about any acute causes for your drop in Ejection Fraction and give your doctors vital missing information.  If this suggests a clear pacing problem, then you and your doctors will have all your answers.  

I don’t know if you have seen the following link on LBB pacing should your doctors ever recommend it:-


I can only find one short Pacemaker Club thread on LBB pacing where another member asked the same question:-


I have also found another Pacemaker Club member with HIS pacing:-


Wise Words

by SeenBetterDays - 2022-05-23 09:03:09

Thanks so much Gemita, that's really kind of you to track down those links for me.  Sometimes the mind does you no favours and it helps to see a calmer perspective.  I will do some more reading and thinking.  Wish my pacemaker had come with some counselling sessions!

Thanks again for your time, it's really appreciated.

Being an engineer, I drill down to the cause of a problem

by Terry - 2022-05-23 13:16:45

CAUSAL MECHANISM cells at the electrode contract toward the electrode. Advancing propagation continues to draw myocardium toward the electrode site resulting in extreme fiber strain farther away from the electrode site, even at rest. Atrophy near, hypertrophy away from the electrode.

Normal physiological ventricular activation by the His/Purkinje system choreographs ventricular activation, endocardium to epicardium and apex of the heart to base.

I was told "I have seen patients with no sign of heart failure, come back right after getting a pacemaker in heart failure." This is not the majority of patients. All the best to you. It's rare to see someone be this involved with their outcome.


Thank You for the Engineering Perspective

by SeenBetterDays - 2022-05-24 13:14:56

Terry I can see you have an in depth knowledge of conduction system pacing and I really appreciate the explanation.  It makes perfect sense to me that physiological pacing which mimics the body's natural process would prevent potential problems further down the line.  I am wondering why some members who have right ventricular pacing for long periods of time seem to suffer no ill effects whilst others' left ventricular function deteriorates quite rapidly. I suppose we are all built differently, and this applies to our hearts as well!  I am wondering whether I should be investigating His pacing as a first option, even though I have read that it's more tricky to achieve and has higher voltage thresholds which can potentially drain the pm battery more quickly.  I can see there are pros and cons to any course of action.  I am also not sure how you find out who are the most experienced conduction system implanting surgeons in the UK - my internet searches so far have proved pretty fruitless.  Thanks again for taking the time to respond.  All info is very much appreciated.  The site you directed me to has a wealth of relevant research.

LV cardiomyopathy due to RV pacing

by AgentX86 - 2022-05-24 14:51:58

There is a fairly simple explanation for this.  It takes some time for the electrical signal to go from the pacing site (apex, normall) across to the LV so the LV contracts just after the RV.

Now, think of a water baloon (your heart) held by both hands (RV and LV muscle).  Now, squeeze the right side and you'll notice the left side buldge out.  Squeeze the left and you'll notice the right do the same.  It's no really that bad but you get the idea.  The time difference in the electrical crossing from the right to left ventricles causes this to happen for at least the first part of the heartbeat. This stretching can cause the muscle to weaken, or even thicken because of the increased stress and work needed to counter it.  This can cause the left ventricle to grow muscle to compensate, which causes other problems.

If this happens, the fix is to resynchronize the LV and RV, which is the purpose of CRT and His pacing. Each has its advantage and both can be difficult to do.

His pacing can't be used for anyone with any electrical problem in or below the bundle of His, so is inappropriate for a His bundle or left or right branch bundle block. It's not unusual for the root cause of the A/V bock to continue down the bundle of His. It's not a silver bullet.

Neither is 100% successful in raising an ejection fraction but they're the best solution.  They go about it in a sliightly different way.

Wait and see?

by Gotrhythm - 2022-05-24 15:25:34

You have had several good replies about various courses of action open to you. I can't add to them but I do wonder if one starting place might be a talk with your consultant to discover what he means when he says, "Wait and see."

Wait for what? See what?

Though it is frustrating to us who want definitive answers and a clear course of action, the fact is that medicine is not always that clear cut. Sometimes, actually a lot of times, symptoms/problems just go away on their own, and any interference is as likely to cause new problems as not and might make the patient worse. Sometimes, if you wait a new symtom appears that makes the course of action crystal clear.

Of course, I'm too am only imagining what the consultant might be thinking. The most rational thing would be to simply asking him what does he mean. What signs is he watching for? How will he know when you do or do not require intervention? What can you do to assist him in getting the information he needs?

It is a fact that around 10% do develop pacemaker induced cardiomyopathy. It's also a fact that 90% do not. I have had a pacemaker for 11 years now, paced 100%, with no symptoms of heart failure, though in the 11 years my ejection fraction has slowly decreased (probably due to my heart being 79 years old now vs the 68 when we started.)

The odds of not having pacemaker induced cardiomyopathy are in your favor. What you need right now, rather than a CRT or a surgeon who can do His-bundle pacing is more information. If you can't get your consultant to share his decision making process with you, then a second opinion is in order so that you can get a clearer picture of where you are.

Food for Thought Thank You

by SeenBetterDays - 2022-05-24 16:27:18

Thanks AgentX86 for your really good balloon analogy, that helped me to visualise what is going on in a much clearer way.  Gotrhythm, you are absolutely right about needing more information.  Unfortunately, as wonderful as it is to have a National Health Service it is frustratingly hard to have any kind of discussion with a cardiologist.  I am "under surveillance" at my local hospital but my next appointment for an echo is January 2023 so not sure if that is a bit too far off.  I am trying to do as much research as I can and will book another private cardiology appointment.  I think the cut off for CRT is an EF of 35% so I guess that's what the consultant is waiting for.  I suppose, from my perspective, I would rather intervene before it gets to that point and try to avoid a further deterioration. Thanks so much both for your input.  It really helps to talk to people with direct experience and knowledge.     

Lots of good information here

by PacerRep - 2022-05-24 20:24:19

I saw your post and thought I would be able to help out here, but I am a day late and a dollar short; some excellent advice here—a few points to highlight just because I am here and not to steal any thunder.

BiV is not an option for you, EF has to be less than 35%. It's a terrible thing to know you have to get worse before you can get better

RV Pacing can cause what you are experiencing. It causes worsening Heart Failure, and can lead to Atrial Fibrillation down the road. Effectively your heart is probably "wobbling" when it's beating right now. I challenge the 90% data above. 

Left Bundle Branch Pacing is far superior to CRT and HIS pacing, in my opinion. You have a case to do this as you don't need to meet CRT criteria for it.

There other device options out there that can help with this, but would need a lot more information before opening that conversation. 


Concern re. Pacemaker induced cardiomyopathy.

by Selwyn - 2022-05-25 07:17:09

Hi SeenBetterDays,

I think from what you have described there is cause for concern.

Your GP should be able to help you find a cardiologist with an interest in His bundle  pacing etc.

The drop in your ejection fraction  needs an explanation. Have alternatives to pacing cardiomyopathy been thought of? 

Whilst my cardiomyopathy is not pacemaker induced, my understanding of pacemaker cardiomyopathy is that the earlier it is managed (by better coordination of the pacing via the two ventricles, however this is done, the easier it is to actually reverse those changes. Whilst your situation is not urgent, you could do with a proper, firm,  diagnosis. Certainly, I don't understand how doing nothing over time is a help.

Under the NHS, you are entitled to a second opinion (talk to your GP), however, having said this, given the waiting times at present, if you can afford the cash, get a private second opinion, as in my experience, it saves a lot of anxiety.  

You will then be able to weigh up the opinions with the help of your GP and hopefully know which direction to go.

So Thankful For Your Thoughts

by SeenBetterDays - 2022-05-25 09:38:26

Thanks so much PacerRep and Selwyn, this club has so many amazing members who provide real support to people going through difficulties.  I really appreciate you taking the time to respond.  The reality is I have practically broken the internet trying to diagnose myself, my GP surgery has taken a much more hands off approach to patient care since the pandemic.  Getting a face to face appointment has become nigh on impossible.  There are also extensive delays in seeing consultants.  The system is under such strain that unfortunately the NHS is struggling to keep its head above water.  I'm sure there are a lot of people with similar experiences at the moment. 

I am not sure how pacemaker induced cardiomyopathy is formally diagnosed - are there any criteria other than the EF is falling and you have a high burden of RV pacing?  

You are right that there may be other underlying reasons for the fall in my EF but I don't think I can get any answers at the moment.  I was never able to establish the initial cause of my AV node block and it may well be that whatever was at work then is still having a little unwelcome party in my body.  Who knows? I suppose my logic at the moment (possibly misplaced) is that if I can improve my heart function I might be better placed to deal with any other ongoing issues.  I have booked a private appointment with a cardiologist to discuss left bundle pacing so see how that goes. I would be interested to find out if PacerRep knows if settings can affect EF levels?

Thanks again for your posts, you have all been a huge help.

Your search for best treatment

by Terry - 2022-05-26 14:17:03

I just scanned the excellent comments. Not haviing gone further, just two options come to mind. Ask your Medtronic Rep for referral (they have the tools for conduction system pacing). Or look up HOPE-HF a study in the UK. The authors have the knowledge and experience.

All the best in your quest for empowerment.


I found these affects of conventional pacing, according to the literature

by Terry - 2022-05-26 14:24:31

Deleterious effects of bypassing the cardiac conduction system

1. Myofiber disarray

2. Fatty tissue and fibrotic deposits away from the electrode

3. Impaired endothelium function

4. Acute hemodynamic function

5. Redistribution of myocardial fiber strain and blood flow, with hypertrophy away from the electrode

6. Mitral valve regurgitation due to poor papillary muscle timing

7. Cardiac sympathetic activity

8. Decreases in LV chamber relaxation

9. Slowing of LV isovolumic relaxation

10. Far LV wall contraction against a closed aortic valve

11. Tricuspid valve insufficiency due to lead mechanical disruption

12. Mitochondrial abnormality away from the electrode

13. Atrial fibrillation


by PacedNRunning - 2022-05-27 04:46:27

My Ep told me the criteria for pacing induced cardiomyopathy is less than 50% EF. I get yearly echos and it dropped from 68% to 53%. Next yearly one was 55%. So I'm hanging on until it drops below 50% then it's upgrade to a CRT. My EP said I do not have to be below 35 % to upgrade to a CRT. We fit different criteria than true CHF but causes by high pacing burden. 

Really Useful Info Thank You

by SeenBetterDays - 2022-05-27 11:22:49

Wow Terry, that is quite a list! The only thing I can think is that some hearts must be more resilient than others and it's a little bit of a lottery as to whether heavy burden pacers end up with cardiomyopathy.  Unfortunately, you often don't have a choice as to what modality of pacing you have when you are in an emergency situation.  Having said that, it would have been helpful to have been given some of this info by the medical team after the initial op as I have only discovered the potential issues and problems which can arise through doing my own research.  Members of this club including yourself have been incredibly helpful in raising my awareness.  Thanks for all your suggestions, I don't have a Medtronic rep but I will have a good read of the HOPE-HF study and see what I can glean.

PacedNRunning, if you have time can you let me know how long you have been paced for just to get an idea on timescales for the fall in your EF.  It's sounds like you are pretty fit despite the pm (this gives me hope!).  Is it cheeky to ask how old you are?  I am 50 and enjoyed an active life before which has been curtailed by recent events.  I suppose I am clinging on to the idea that I could get my old fitness levels back and wonder if I am being unrealistic.

Thanks so much for taking the time to add in your comments both of you.  Really appreciate it.

Full disclosure

by Terry - 2022-05-27 17:20:17

I have been working on implantable devices since a close relative was born with a heart defect. That is, 50 years, mostly pacemakers. I do not have a pacemaker implant, but I feel an obligation of conscience to shine the light on the science of pacing when doctors won't. So glad more doctors  are, and at an exponentially increasing rate. Enough said, but if you are still curious, see: <Terrell M. Williams - Marquis Who's Who Top Engineers (marquistopengineers.com)>.


worked for me

by dwelch - 2022-05-27 22:11:37

btw nice to see Terry here, welcome, hope to read more of your comments.

I am 35 years in, on pacer number 5.  It took me about 30 years for my ejection fraction to get to the mid 30s starting in the mid 40s when we started watching it 15 plus years ago.  So relative to your situation Terry seems to know a lot more.   Got a biventrical and my ef not only stopped but went back up.   Was told that it may or may not be the pacer, and here is what we are going to do.   I always say find a doc you trust, trust the doc you find.   We have lots more combined experience that the docs in some respects, but the doc you have or docs near you may or may not be able to do what others somewhere else can.  And I assume it might not be 100% possible to determine if it is the pacer or not that caused this change.  but doing nothing wont make it better.  So there is no right answer here IMO, but in my specific case, it appeared to be a somewhat expected result of decades of LV pacing and a biventrical helped.  

Mind Blown

by SeenBetterDays - 2022-05-28 10:33:09

Terry, now the technical knowledge all makes absolute sense! Having read about your incredible engineering achievements I am slightly in awe.  Thank you so much for all the work you have done and continue to do and for taking the time to help people like me.  

Thank you dwelch for the advice.  It seems that you have been part of this pacing world for quite some time now. You are absolutely right, I can't fix it by doing nothing so will seek out some more medical advice and fingers crossed make the right decision.  So glad the biventricular worked out for you.


by Terry - 2022-05-28 14:33:51

You make it feel all worthwhile. It's all about you and your willingness to engage openly.


To answer your questions.

by PacedNRunning - 2022-06-01 06:41:41

I'm 50 also. I was 46 when I got my pacemaker. I started out pacing intermittently anywhere from 37-50-% of the time. By 2 years paced I was at 100%. My first echo post implant waa 68%. 18 months later 53%. My EP said the difference was being paced 100% vs intermittently. Most recent 55%. Whew. I worry about that also. But I do have high septal wall placement which has good results. I'm young, active etc. few things on my side. I was a runner before my PM. Took a while to build stamina and I can be pretty tired after 60 mins of running or cycling. But I can still do all the things, just not as long. With your doctors approval you could go back to exercising and building stamina. Just take your time and increase as your feel good. 

I have read that if we don't develop PICM in the first 5 years, our risk goes down significantly. Those that developed PICM already had some sort of LV insufficiency. Also seen in those with SSS and no AV BLOCK. The key is unnecessary pacing. Those in the studies were being unnecessarily paced. Make sure your AV delays are appropriate for your block. I've done enough reading that our settings can improve EF/cardiac output. 

AV Delays

by SeenBetterDays - 2022-06-01 10:45:47

Thanks PacedNRunning for taking the time to respond.  That's great that your EF seems to be levelling out despite the high pacing burden.  I think if my reading was above 50 I would be more inclined to wait and see but because it has dropped to 45 and I'm not able to exercise as I used to without chest pain and breathlessness I feel as though PICM might be kicking in.  I asked my EP to try out rate adaptive AV delay in the early stages as I thought it might help me (initially I felt better but then the symptoms recurred) but I'd be interested to know if you have a fixed AV delay and whether that might have any impact. You sound like you have done some homework on settings so probably know a lot more than me! Thanks again for your time. 

Rate Adaptive AV

by SeenBetterDays - 2022-06-01 11:33:44

Sorry I should also have included my parameters min PAV 140ms and min SAV 110ms with rate adaptive AV on.  If you can spot anything obviously amiss with those settings from your perspective that would be really helpful.  Cheers


by PacedNRunning - 2022-06-03 02:58:49

Hi there. There are many articles about AV delay and how it can affect cardiac output. If they are set properly it can help increase cardiac output. My delays are dynamic since I exercise. My SAV 60-150 and PAVD 80-170. I've tried my shortest delay (which is the exercise faster rates) from 60-110ms. 80-90 felt the best but 70 felt great! I'm at 60 because my Max Track is 185bpm. I'm set 50-185 which makes a difference when talking about dynamic delays. I'm guessing your max track is somewhere between 130-150?  Hope that makes since. Basically the AV delay shortness from your longest set.. for me 150ms and continues to get showers are your HR increases. So from 50-185bpm my AV delay starts at 150 and becomes shorter as my heart increases and caps at the min 60ms. I don't think fixed would ever work for me. I totally rely on pacing and need that dynamic. You may not pace at higher rates so the dynamic may not matter. Hopefully your team knows your activity level and can adjust the AV delay to accommodate higher rates. 

The Quest for Knowledge!

by SeenBetterDays - 2022-06-03 17:21:28

Thanks  a lot PacedNRunning for taking the time to answer my questions.  I think I need to research more.  I had to persuade my EP to increase my upper HR to 170, my lower rate is set at 60.  I think they don't always consider someone's age and level of activity when they decide on settings.  This is very frustrating when you are used to exercising and everyone is telling you that after the pacemaker you can just get back to all your normal activities no problem.  Maybe for some but absolutely not for me.  It sounds like you have a good team of people who have actively listened to your individual needs - wish that was the case across the board.  Thanks again for the insight, I'll go back to the books and see if I can find out more.

You know you're wired when...

You play MP3 files on your pacer.

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