Increased level of junctional beats after upgrade to 3rd lead added to Left Bundle Branch

I recently (12/9/20) was due for a replacement pacer and was "upgraded" from a Medtronic 2 lead Revo unit to a Medtronic 3 lead Serena unit. 

The main reason I went for the 3 lead unit was the increase in pacing in the ventricles with the 2 lead Revo unit. I decided to get what I hope are the benefits of synchronized vent pacing over time instead of fighting cardiomyopathy later on- my choice. 

Regardless, a bigger issue I had prior to this upgrade was junctional rhythm, competing with the pacer. I could never tolerate a rate over 60 bpm, and my junctinoals hover right around 60 bpm or so. So, basically I have lived with the bouts of pain that the junctionals bring me when under stress, etc, as a trade off. 

With the new 3rd lead added, I am at a rate of 60bpm. During interrogation of the pacer, at 60 I over run most junctionals, maybe 70%. But, put me under stress, and I go back into full junctionals. 

I had the EP turn the pacer up while there for the interrogation up to 70 bpm, and sure enough, I my heart rate was outrunning the junctionals, probably 95% of the time. But, just sitting there in the EP office for 10 minutes at 70 bpm, I just feel a heavyness in my chest that I dont feel beating at 50/60bpm. So, I choose a route to take for a test- leave the pacer at 60bpm and now am trying a common Beta Blocker which there is plenty of info here on our site, Metoroprolol. 

I just started the beta blocker today, so I cannot at all report any result. The hope is that any junctionals that get through at 60bpm will be taken care of by the beta blocker. 

If that does not work, then I am going to give 70bpm a try for a few days, just as a last try before I seriously consider a much not wanted ablation. 

The point of all this data is that my experience since receiving this 3rd Left Bundle Branch lead is that my junctionals are alot more consistent and symptomatic(meaning chest pain) than when I had the two lead pacer).

The EP of course, as good as he is, does not have a pacer in his body and does not understand other than technically this should not happen. But, it is, it is what I am experiencing. 

This is probably a niche question, one would need to be upgraded from a 2 lead to 3rd lead pacer, but I will throw it out there:

Anyone notice an  increase in the duration and symptoms of junctional rhythm after a 3rd lead was added to your heart?


Junctional beats

by Gemita - 2021-01-06 15:29:47


Hello, yes your question is so very specific and would I imagine prevent many members from even attempting to respond to your post which is such a pity. 

I do not have a third lead and therefore I am not really qualified to answer your post, am I?  However to get things started I would like to make the following observations.  

Your upgrade to CRT is very recent and therefore you are still in the healing period.  I would expect you to experience many unwanted rhythm disturbances during the healing period that should hopefully resolve within a few months once synchronised pacing settles down and your heart gets used to that third lead and to the trauma of the implant procedure.  

As the junctional rhythms cause so much discomfort I would go initially with a higher heart rate setting, since you and your doctor can see this clearly works and has shown a vast improvement already in controlling your symptoms.  You say at 70 bpm your junctional rhythms were almost completely controlled.  

In my experience as an arrhythmia sufferer, a higher heart rate is for me one of the most beneficial ways to outpace many of my arrhythmias, far more effective than taking a beta blocker which may make my rhythm disturbances far far worse.  It is the slowing of my heart beat that can trigger many unpleasant heart rhythm disturbances and by increasing my heart rate, my rhythm disturbances settle quickly.   What have you got to lose?  I would try it before moving towards an ablation. 

I am taking cardio selective beta blocker Bisoprolol (which mainly targets the heart rather than other organs, especially at low doses), so fewer side effects.  Low dose Bisoprolol helps prevent my rapid ventricular response rate and calms my arrhythmias.  My heart rate is set at 70 bpm day and night.  What a difference it has made.  I have SSS/Tachy/Brady Syndrome.  I believe Metoprolol is also a cardio selective beta blocker.  I would ask for the lowest possible dose if your doctor agrees and I would go with the highest heart rate setting you can tolerate for a brief period to see whether this helps.

I hope you have had some basic blood tests carried out to rule out causes such as electrolyte imbalances (a frequent cause), thyroid problems, anaemia, infection?   

I don’t know what else to say except good luck, learn to relax, breathe slowly and deeply, drink plenty of water, get good quality sleep, fresh air, exercise, stick to a healthy diet.  With the right internal environment how can rhythm disturbances survive?

Yes, I am looking for someone that would have this rarity of a situation

by jds66 - 2021-01-06 19:01:13

Yes Gemita, I thank you for your reply. Well thought out as you always are. 

I am truly trying to gather data and am absolutely going to try 70 bpm once I get back to the EP on 1/15. I have my doublts that the Beta blocker is going to do much, but after less than one whole day of taking it, I am guessing. (and basing my guess on my unsuccessful experiment with the same beta blocker in 2013).

I just find it odd that the pain of my junctionals has gotten doubly worse since the 3rd lead was added. Almost like they poked the bear and now the bear is growling and making its anger heard, in the form of extra pain. 

I did notice on my interrogation readings yesterday that my AS-VS readings, which for those that dont know what that is, that reading is telling you how much your actual native conduction is working for you. So, for me, the last year or so of my 2 wire pacer, my AS-VS readings were trending downwards, to about 9%, which means my heart needed help from the pacer 91% of the time to beat in either the atrium or both atrium and ventricles. 

Now, with this new 3 wire Bi-V pacer, lo and behold, my AS-VS reading yesterday was at 24.8%. Which made zero sense to me. The third wires should have no bearing on how much I pace, just that it will pace both ventricles properly. 

I thought maybe this number was a GOOD sign, and asked the EP. He said no, that number now is showing that junctionals have taken over and now they are running the show 24.8% of the time. Really what that means is that I am having more painful junctionals because I am in them a significant more period of time. The junctionals are basically being interpreted by my pacer as a natural rhythm and the pacer is not doing anything to counteract them, since my low rate may be too low to out run them. I know, confusing as hell to me also, but I know my pain well at this point, and this pain is way more sensitive and consisent than before my new pacer a month ago.

So, I will be trying that 70 bpm low rate, and reporting back here. 

My last thing I will try before avoiding that ablation is having them turn off the 3rd wire and have me go back to AAI=DDD pacing, and see for myself that maybe that third wire is the culprit of my extra junctionals and pain. Wouldnt that be a crappy thing! Fix one thing, and make something else worse!

Either way, I am stuck living with the pain, until I find the right combo. I hope the 70 bpm rate does it, I dont know. 

PS-I have been a member here long enough, though not posting much the past 8 years to remember a wonderful, unfort passed away member who was a legend here, his name here was Electric Frank. He was kind enough to share his personal email with me back in 2012 and he was so helpful. I am here in the spirit of Electric Frank, trying to help others where I can. Gemita, keep up the good work, you are helping many here also, Electric Frank would have liked your style!

Junctional beats

by AgentX86 - 2021-01-06 19:01:16

You've figured out most of what you need to know.  Junctionals are quite like PVCs and are treated much the same way.  A beta blocker is the best idea, if you can tolerate it.  Many can't.  They make many intollerably lethargic. Changing doses or switching to a different beta blocker usually help. 

You've tried uping your PM rate to 70bpm and didn't like it.  I understand completely but you would get used to it.  I went from 40-50bpm to 80bpm, then to 70, and back to 80 to escape from the PVCs.  I've been at 80bpm for two and a half years now.  I've had them drop it to 50bpm at night make it easier to sleep.

BTW, I have a two-lead PM with the two leads being equivalent to your second and third (no lead in the right atrium).  That is, I'm paced in the ventricals only but have a biventricular pacemaker (VVIRV mode).


by AgentX86 - 2021-01-06 19:13:15

I guess I'm confused by the AS/VS reading.  Why would sensing in both do anything?  No pacing is going on.  I could see an AS/VP increasing perhaps because AS to VP timing is too short.

As far as AAI or DDD, why don't they try putting you back to AAI?  If you don't have a heart block, DDD isn't doing anything for you and even if you do, AAI will work.  Some hearts don't like DDD.

Valuable comment to me AgentX86

by jds66 - 2021-01-06 19:13:37

You hit the nail on the head well there, AgentX86, my relucatance to go to a higher rate. And appreciate your story about what rates you have tried. 

Very similiar to my situation. I am lucky, like you, in that my new pacer does have sleep hysteresis mode, which I had them setup yesterday (funny enough, I had to help my EP program it and find it on the Medtronic unit, I know the machine that well).

I am tight with my EP.  I will have him turn my up to 70, then he will let me hang around the hospital complex a couple hours in case I change my mind. I think if I leave them, maybe go exercise a bit, and then see how I feel knowing I can get it turned down that same day may get me over the  hump. Just my limited experience at 70 has not been good, but well, not long enough for me to form a good opinion so I will bascially make myself do it, since it is part of the data I will gather before moving fwd. 

And, intersting your sleep mode was all the way down to 50bpm. I was worried that when I put it at 70, I was going to change the sleep rate from the current 50 to 55 bpm. since I am worried that the morning ramp up of 20 extra heart beats would be enough to wake me up, say on weekends. 

How do you tolerate raising 30 extra beats from 50bpm to 80 bpm when you wake up in the AM or more importantly, how does it feel if you are still sleeping and 80 bpm kicks in before you awake?

And, to answer your most recent post. I have heart block bad enough they are afraid of using just AAI mode with me, they wont do it in fear I would pass out or worse. 

Great info, hope to hear your reply. I see you are here alot also- in my limited time back and offer good advice, ElectricFrank would be a fan of you too!

Night mode

by AgentX86 - 2021-01-06 19:24:20

I don't have any trouble with it.  It's set to go to night mode from 12:00AM to 6:00AM.  This morning I got out of bed at 5:00AM ], dessed, and walked my daily10mi before breakfast.  No problem at all.  I have my RR set pretty agressively so it kicks into high gear quickly.  I'm at 110bpm before the first quarter mile. I haven't checked precisely before the top of a hill at the 1/4mi mark.  It remains at ~110bpm for the next 3hrs.

In my last post, I essentially asked if you had a heart block.  I see by the subject that you have LBB which is sorta similar but not.  I would think you could still go back to AAI.

Your an animal!

by jds66 - 2021-01-06 19:54:34

Up at 5a- daily 10 miles!  Agentx86 you make my 6mile walk today look like a toddlers effort! Keep it up!

I have heart block bad enough that the EP is not willing to go to strictly AAI mode- so no dice there. 

back to you- again my question about your sleep mode. There must have been a time that you slept later than 6a in the early days of your pacer where going from a rate of 50 to 80 while still sleeping would have woke you up?

Sleep mode

by AgentX86 - 2021-01-06 23:49:21

When I'm working (mostly at home, now with covid around), I'im usually get up at 5:45.  This morning I couln't sleep, so got a jump on it.  I have a 9:30 meeting tomorrow morning so will do it again tomorrow morning.  On weekends and all last month (vacation - use it or lose it) I didn't et out before 7:00AM, often 7:30.

Sure, I like to sleep as much as the next guy.  Then it rains (not often in the mornings) I sleep in until, maybe as late as 10:00.  I do wake up but I don't think my PM is the cause.  I wake up fairly regularly at night, too, bu roll over and go back to sleep. I've been doing that for years.  The higher heart rate dosen't seem to bother me once I first get to sleep.  Last night was quite unusual in that my heart was pounding at night and I woke up at about 4:00 and couldn't sleep after (couldn't stop thinking).


by Gemita - 2021-01-07 06:49:30

It would be a pity to have them turn off your third lead and to leave it off after you have made such a strong case for the benefits of cardiac resynchronization therapy and after going through the implant procedure, although as a temporary tool to get further information on the nature of your junctional rhythms it might be helpful to try. 

I wonder if they have got the optimal lead tip contact position for that third lead, but I expect you have had lots of pacemaker checks to rule out any lead sensing problems.  I am still hopeful this will settle with time and outpacing measures before you try to slowly, gently reduce your heart rate setting to a more comfortable level for you. 

My feeling is to forget a lower night setting. Keep heart rate steady round the clock.  A sudden heart rate switch to night mode settings could trigger an increase in junctional rhythms, so this would disturb your sleep in any event.  Keep it simple and steady 24/7 is my advice, but what do I know except what works best for me !

Yes Electric Frank was a wonderful contributor, a heavy weight when it came to understanding the “electrics”.  I often come across his postings when I use the search facility.  But we have a lot of excellent contributors here with us today on Pacemaker Club who I have a lot of respect for and enjoy reading their posts.  I am just someone who cares and wants to help others in whatever way I can based on my own limited experience of having a pacemaker.   My contributions are really more about “symptom experience”, experience with meds, treatments, doctors(!), health conditions (of which both hubby and I have many), rather than what “little” I know about pacemakers/settings.  Settings, technical data still a work in progress for me unfortunately.  You sound as though you go back a long way and know your body and pacing needs very well.  You also write with clarity and ease and I enjoy reading your posts.

I am mostly pacing in mode AAIR until my pacemaker detects an atrial tachyarrhythmia and then switches to a non tracking atrial mode, switching back to AAIR when the arrhythmia ceases.  I feel these switches and hate being paced in my right ventricle and feel so much better when I go back to AAIR mode pacing.  Although I have some LBBB and RBBB, these are only intermittent I believe.  My main problems stem from my many arrhythmias which often seem to make my LBBB/RBBB more likely to occur.  I also still have pre-syncope spells and have a long history of syncope from both vagal and electrical sudden disturbances. 

SSS/Tachycardia/Bradycardia syndrome was officially diagnosed in 2016 but my difficulties with heart rhythm go back years but have been particularly hard to detect because of the intermittent nature of my arrhythmias.  Reveal Linq implant loop monitor in 2015 changed all that and gave my EP invaluable information and me my much needed pacemaker


by AgentX86 - 2021-01-07 17:54:07

I believe you said before that you switched from AAIR to DDDR?  Now you say it switches from AAI to AOO or VOO (non-sensed)? DDD is still sensed (in both RA and RV).  Am I still missing something?  Just trying to understand different pacing strategies.


by Gemita - 2021-01-07 20:04:02

Mine switches from AAIR to the non atrial tracking mode DDIR during a tachyarrhythmia and then switches back to AAIR on cessation tachyarrhythmia.  Does that make more sense?  


by AgentX86 - 2021-01-07 21:20:02

It wasn't clear at all so I did some research-


Essentially, when it detects tachycardia (faster than expected atrial rate) it switches from AAI to essentially VVI.  It's no wonder that you don't like it.  You're switching in and out of A/V synchrony and doing it just when you're already having a bad time.

Even more confused !!

by Gemita - 2021-01-08 04:26:51

AgentX86 my paperwork has me down as AAIR to DDDR but switching to non tracking mode DDIR during atrial tachy arrhythmia.  Sorry does your link still apply?

The in and out switching so frequently, due to the nature of my arrhythmias, is really destabilising.  I am still waiting to receive my last pacemaker full download that I requested in October, for details of mode switches and other essential info but I can clearly see that I need to speak to my EP to confirm what actually happens when I mode switch. I need this confirmation for my own peace of mind because clearly I become extremely symptomatic during switching.

I am really grateful that you are challenging me on this because it could help me to get to the root of my problems 


by AgentX86 - 2021-01-08 13:34:52

When I read the article, it sounded exactly like what you have.  It may be called DDD but it seems that it's closer to VVI, or some cross between the two.  DDD and DDI imply that you're sensed in both the atrium and ventricles and the pacing is inhibited when a natural pacing signal is detected.  In the case of Afib, or similar, the way I read it is that sensing is stopped in the atrium and it's paced AOO, with the ventricals trying to follow along.  So it may be something like AVI? or ADI?  The effect is that you're going to get something akin to VVI because the arrhythmia is probably going to out-pace the pacer.  The article mentions that this is sort of a pseudo-VVI.   At least that's how I read it.



by Terry - 2021-01-11 14:34:38

Hi JDS66, you said you were "upgrade to 3rd lead added to Left Bundle Branch." This is very different from CRT, actually much more advanced. To understand exactly what your EP is doing, you may want explore the physiology of left bundle ventricular activation. For papers on left bundle branch pacing, scroll down to "His / Purkinje system pacing matures to include left bundle branch pacing for some patients" at <https:///>. CRT is interventricular synchronization, but LBB pacing is for natural physiological left ventricular activation.

Thank you Terry

by jds66 - 2021-01-12 14:21:30

I actually have the 3830 lead that you invented in my LBB, so thank you for the efforts!.

I have an appt this Friday with one of my 2 EP's (my main EP implanted my first pacer in 2012, the Revo, and he referred me to this more advanced EP for the 2020 LBB lead and new pacer- funny enough, my doc is actually referenced in one of the papers in the link you included).

I may have some of the terms wrong, as you point out, so I apologize for that. 

My main EP thinks that I have concealed bundle extrasystoles originating from the bundle of HIS. That is what, in his guess, is causing my ventricles to go faster than the atria, put me into junctionals, and then as a by product pain. This was my condition before I got the new LBB lead, so should have nothing to do with anything. 

But, I have noticed the junctionals caused by the concealed extrasystoles from the Bundle of HIS are ALOT more painful and often since the LBB branch lead was placed last month. 

I am trying to figure out if that has any correlation- and honestly, trying to avoid an ablation. I was in the hosp for an ablation last month, the more advanced EP thought he saw a setting that was causing my junctionals (MVP was on, he said in my condition, it should have been off). Turned that off, instead of ablation, he put a new LBB pacer in me (I had a high rate of V Pacing over the past few years, but with no real symptoms), and now I have real bad junctionals and pain worse than before. 

Hoping to get some insight on Friday appt, where I also will try to up my low rate to 70bpm, from 60bpm, as my EP says my junctionals tend to overtake me right at about 60bpm. 

Thx for your input. 

You have worked for and deserve the best

by Terry - 2021-01-12 19:25:38

Wow, you are one of the most well informed patients I have encountered. I believe it will pay off for you (and your loved ones). Perhaps you can keep us all posted after your next appointment.



Update after 1/15/21 EP visit

by jds66 - 2021-01-17 13:54:09

Well, nothing great to report. My EP said my heart block had progressed from first degree to third degree the past 8 years. We kind of knew that already, just looking at my AP-VP rates greatly increasing over the past 8 years, I actually think I can pinpoin the heart block progressing, Terry do you backup my hypothesis? here it is:

My AP-VP numbers went steadily up every year since 2016. 2016 AP-VP 25%  2020 AP-VP 80%. To me, that is something progressed, I will chalk it up to increasing heart block, am I on the right path?

Meanwhile, I had the low rate set up to 70 bpm. After one day, I felt okay, some junctionals were still getting through, I could tell by chest tightness. 

But today, I really felt them badly again, chest go real tight and even breathing in fully was difficult, which is not normal for me. 

Again, my EP's both say it isnt dangerous, the heart "beating backwards" as they say. The atria is pushing blood and then since my junctionals take over strongly, the ventricles are shutting the valve off and the atria is pumping agian, and that valve that the ventricle controls is stopping the blood from the atria coming down, causing the pain. Has been for years. A pacer cannot over come junctionals - if it could read your mind and know they were coming, perhaps it could, but my pacer cannot overcome them. 

So, I will have them turn me back down to 60bpm when I have my next appt on 1/20/21(the advantage of having 2 EP's involved, lucky I can get in this often to do my testing. )

My theory on the pain being worse at the higher rate- more "backwards" beats per minute (70 vs 60), the more painful instances per minute are created with a higher heart rate. 

My EP will also be bringing me in for a more detailed study with the Medtronic machine to determine exactly how bad my heart block is. From there, we will see what happens, but I am hoping that going back to 60bpm helps me just calm things down. 

I can deal with the pain(somewhat) and still work, but at 70 bpm, it is alot worse. I am still hopeful of avoiding the ablation- and may just take some time to heal and see where I am at in a few months. Once they ablate, and it doesnt work, you cant recover from that. (yes, some ablations do work, but until I am just about disabled from pain, I am not signing up for them)

Tinkering with settings and medications are reversible, I am trying that course for now. 

Increasing HB

by Terry - 2021-01-17 14:51:46


Thanks for sharing your complicated case. Being a pacemaker guy (and if I have a hammer, everything is a nail) I stray from your question, wondering if pacing the conduction system a little higher, at the His bundle, before it branches to the left and right bundle branches, could keep ypur conduction system busy, preventing retrograde atrial conduction. I believe your EP knows and will tell you if that is the case.

Ablation can be scary, especially if they don't know exactly where the retrograde pathway is. Is it WPW syndrome? (Look that up on your browser.)


PS: Did I tell you my website? <>. And on Twitter: @PacemakerPAG.

Thanks again, Terry, for your valuable input

by jds66 - 2021-01-17 16:56:36

And, I have been all over your website! Great website, and obviously, very interesting to me. 

Maybe I am misreading, but to clarify, my 3rd lead was put in the Left Bundle Branch, not HIS pacing. 

The ventricle leads I know can be altered with timing, similiar I would guess to an AV delay feature. 

My EP's words "my theory is that you have antegrade heartblock with retrograde conduction". Which, in his thinking, may be coming from the concealed extrastoyles from the Bundle of HIS (again, his guess, he is not sure, but best guess)

I did some reading of the antegrade heartblock and retrograde conduction, and a couple papers mentioned that there is a way to get readings from the Bundle of HIS. 

Now, I cannot imagine, other than doing an EP study that they can tell if a beat originates from the Bundle of HIS vs higher up, but maybe with newer technology, they can, other than going in with a catheter?

I did some perusing of WSW, not sure if that is where I am at, but I will mention that to the EP. 

Both EP's are sort of agreeing, but using different terminology, but they are both in agreement that what I have is quite unusual. One is ablate happy, the other is taking a much more, "lets really see what we have and try every possible angle, even do an EP study and not ablate if we cannot recreate the condition).  

Obviously, I  prefer the second EP's strategy, even though they may both be technically right. 

Again, thanks, your input is very gracious, and I hope others reading get some useful information out of it also. 

Retrograde Conduction

by Terry - 2021-01-18 19:44:00

What if your retrograde conduction originates in the His bundle, within the right bundle? (Note that the left and right bundle branches are insulated from each other and are within the His bundle.) If you had His bundle pacing (not the left bundle in the interventricular septum like yours) and since the His bundle, containing both left and right bundles, is refractory for a time after it is activated, wouldn't the refractory His bundle make junctional beats originating within the right bundle, (inside the His bundle), make retrograde conduction impossible (during His refractory period that is)?  

Look up "cardiac conduction system" to visualize the anatomy.

I have the same problem ever since upgrading to his pacing and I had a 3rd lead as a backup in my left bundle.

by RwB15 - 2021-01-19 10:53:19

Hello, I am 21 years old and have a pacemaker due to damage acquired in an ablation for tachycardia. I had a dual-chamber placed in 3 years ago. 1 year and a half after getting this pacemaker, I developed pacemaker induced cardiomyopathy (PICM). This was sad because I am a baseball player in college. My heart function dropped from 65% down to 38%. So upgrading to avoid cardiomyopathy is smart! The only problem is I have had the same problems, but there has been no data shown on my device interrogations. I have recorded .05 PVCs which makes no sense because I have so many uncomfortable skipped beats and it is always when I am resting. It makes me feel awful and I just want it fixed. I am going to another EP to have him check this out. I also want to mention that I will have stem cells put into the site of my heart block to potentially restore my AV node conduction. I will keep everyone posted because this could help people like myself with heart block. I will tag below the link to my GOFUNDME to raise money for the procedure since it is so expensive. I hope for healing for you and if you could just please at the least share my link for me. Below is the link, just copy and past it to donate or share. Thanks!


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