Pacemaker settings and underlying rhythm

Since my PM implant in July I've been back several times at various places for device changes. The process I've experienced is:

- the device tech connects to the PM (in my case a Boston Scientific)

- changes/adjustments are made either based on my input or on an exercise stress test

- the device is programmed with the new settings

A visit report is produced. There's a lot of data there including the changes made and current settings. There's also quite a bit of information/graphs/etc of readings since the last device check. 

One thing I've noticed is a section at the very top labeled "rhythm". For me, this has been all over the map: "SB 38 bpm"; "SB with 2:1 AV block"; "Sinus rhythm with occasional Mobitz II block", etc.

It seems borderline impossible to me that my underlying physiology has changed that much in four months and seems much more likely that this is a result of the PM settings during that interval. Does this make sense

It seems to me that a smart device tech can program the PM to produce just about any heart rhythm.

The reason I'm asking is the last report showed a very high level of RV pacing. Settings were changed but given how the process works I've no idea whether they're better or worse without going in for another device check which seems sort of pointless (only to satisfy my curiosity). I generally feel "OK" and the PM is responding more or less normally so I'm thinking I'll just wait until the next device check.

Another possibility would be to push the button on the bedside monitor to send them data and produce the report. For those in the states, does this generate a bill to insurance?


Electrical Disturbances or Pacemaker Settings ?

by Gemita - 2023-12-03 13:36:12

Aintgotrhythm, you ask:

It seems borderline impossible to me that my underlying physiology has changed that much in four months and seems much more likely that this is a result of the PM settings during that interval. Does this make sense?  Yes and no. 

Our electrical disturbances are more than capable of changing in four months without any intervention as most of us know which is why we have pacemakers.  That is the nature of electrical disturbances - they never stay the same. 

Of course it is also true that our settings (like mode of pacing, arrhythmia interventions, AV intervals and other complex settings) can have a major impact on how well our hearts behave and can cause all manner of difficult symptoms and rhythms too.  I think this is why when we first set out, it is wise to go slowly, not to change too much all at once, maybe even to go with factory settings for a while to test how well basic settings might work for us before slowly introducing settings changes.

There is no doubt in the presence of any arrhythmia or any electrical disturbance like intermittent block or sinus node disease our technicians will have a difficult time to adjust our settings to suit us.  Additionally, our medication, lifestyle and other health problems could all affect our pacing experience too.

I would ask yourself, how do you feel now?  Do you feel better than when you started out on your pacemaker journey or worse?  If worse is this due to your settings or due to a deterioration in your heart or other health condition?  Then try to treat whichever one is the most likely cause for your worsening symptoms.  

For example my heart rhythm disturbances have improved and my pacemaker settings have remained unchanged for some months now.  When my heart rhythm changes, I don’t go running to the electrophysiologist to change my settings, or assume it is due to settings because I know the nature of my arrhythmias only too well. Instead I try to control my rhythm disturbances first through other measures and if this fails and I become really symptomatic, only then would I seek help and advice from my clinic. 

I sometimes feel that being too focussed on our data can cause problems for many of us.  Let us go live our lives and not to watch those percentages too closely.  Our symptoms will tell us when we are in trouble


by piglet22 - 2023-12-05 05:16:43

Your condition can change overnight.

If you think something has changed, then follow it up. Clinicians are not always good at passing on information even when they are aware of significant changes.

Fine tuning settings in the UK at least is becoming a luxury as pressure on all departments increases.

I've seen the service and time allocated to routine check ups go from very good to frankly non -existent over an 18 year period. Annual remote downloads are no substitute for face to face clinics.

It's sorry to say that you can't assume that someone is taking a close interest in your individual circumstances.


Gemita - I respectfully disagree

by Aintgotrhythm - 2023-12-08 22:44:19

You wrote:

I sometimes feel that being too focussed on our data can cause problems for many of us.  Let us go live our lives and not to watch those percentages too closely.  Our symptoms will tell us when we are in trouble

And also said:

I would ask yourself, how do you feel now?  Do you feel better than when you started out on your pacemaker journey or worse?

My response:

Since implant at the end of July I've been back SEVEN times for settings adjustments. Three of those were with an Electrophysiologist and Boston Scientific rep and were either treadmill or exercise cycle stress tests. The other four times were for "tweaks" or "resets" because the settings were either somewhat anomalous or just crazy wrong.

So how do I feel now?

Well, since you asked. Consistent (though not constant) light headedness/dizziness. Fluttering sensation/pressure in my chest. HR spikes to 140 (note that this is my Max Sensor Rate) on a relaxed walk out to get the mail.

I'm willing to admit that I'm an "outlier". Probably not many people with PM's ride a bicycle 400K with 4000 meters of climbing in less than 20 hours so I'll freely admit that getting my settings "perfect" is going to take some trial and error.

But we're not even in the ballpark. Sitting at my breakfast table I'm being paced at 75 BPM and have a fluttering sensation in my chest that causes me to cough on a regular basis and I'm lightheaded. 

So if you don't mind, I'm going to continue to collect data to try and get to some settings that work most of the time. At this point I've given up on feeling good, I just don't want my HR to spike to 140 when I walk up one flight of stairs.

If I had a do-over I'd probably not have gotten the PM. Am I "better"? Well, that's a tough one. It certainly isn't a given that I'm better with than without the PM. 

The process of "tuning" the settings seems borderline idiotic. Make a change, "how does that feel"? Most of the time I can't tell any difference. Take a lap around the clinic. Assuming I don't fall over dead it's pronounced good.

Once I get some settings that *mostly* work I'll be happy to just ignore the thing and let it do what it's supposed to do but nobody is going to convince me that a relaxed pace walk causing a HR of 140 is "normal".


by Gemita - 2023-12-09 01:27:38

Aintgotrhym I am sorry if you have been offended by some of my comments.  That was never my intention.  I was trying to answer what I understood to be your main question and I quote:

It seems borderline impossible to me that my underlying physiology has changed that much in four months and seems much more likely that this is a result of the PM settings during that interval. Does this make sense? 

I was “trying” to say that it was possible for electrical disturbances to behave in this way, to change rapidly and that this wouldn’t be anything unusual.  This is the nature of electrical disturbances and I respectfully stand by this comment.  I have lived with electrical disturbances long enough to know that they can change in a flash without any obvious explanation.  

You further went on to state in your post and I have highlighted the bits that stood out for me:

The reason I'm asking is the last report showed a very high level of RV pacing. Settings were changed but given how the process works I've no idea whether they're better or worse without going in for another device check which seems sort of pointless "only to satisfy my curiosity".   I generally feel "OK" and the PM is responding more or less normally so I'm thinking I'll just wait until the next device check.

Based on these comments, I saw no real concern for an urgent check, or concern for your well being.  

Now you are telling me that you not okay that you are still experiencing frequent light headedness/dizziness. Fluttering sensation/pressure in your chest. HR spikes to 140 on a relaxed walk to get the mail.   With respect, why didn’t you say this in your message and make it clear that you were not feeling okay?   I would have told you whatever the cost of doing a download, even if only to satisfy your “curiousity”, to do one and to keep doing them until you start to "feel" better.  I would certainly not have told you to "ignore your symptoms".

My messages on this site have always been to "listen to what our body is telling us and if we are feeling unwell, to seek help".  Indeed my final sentence in my earlier comments on this thread clearly state:  "Our symptoms will tell us when we are in trouble".  You are clearly still having symptoms Aintgotrhythm, so of course you should continue to seek answers.

Not offended, only frustrated

by Aintgotrhythm - 2023-12-09 05:56:04


Although it's true that I did say that I "generally feel OK", unfortunately that was only briefly true. The narrative is:

- Oct 3 - PM settings at Mass Gen with exercise physiologist and BS rep

- Nov 8 - PM settings at UW with electrophysiologist and BS rep

- Nov 14 - PM settings at Mayo clinic

The Oct 3 session was to try and fix HR anomalies while cycling. My HR would drop 15-20 BPM in the middle of hard efforts. It was "mostly" successful.

The Nov 8 session was to address the HR spikes I mentioned where it would shoot up to max sensor rate (MSR) during light activity. I thought this was fixed when I made the "mostly OK" comment in my post

The Nov 14 session was to reduce what the cardiologist at Mayo saw as unnecessary V-pacing.

I thought the "HR up to MSR" was fixed by the Nov 8 session but experienced it again just prior to my 8 December post and that's part of what prompted my response.To be honest, at this point I could live with the other symptoms I mentioned (fluttering sensation in chest, lightheadedness) as long as I didn't have the other, more significant anomalies.

But to the topic at hand (collecting data). I'm trying hard to be a "good patient" i.e., rather than go in with a vague "I don't feel good" I'm trying to provide as many specifics as I can. I take my blood pressure every morning, I wear a pulse oximiter at night, I keep a journal of this information plus my daily activities (rides) and overall how I feel.

Frankly, although I confess to being analytical by nature and somewhat of a data geek, it's a chore to do all of this and that's why I closed with the comment that once I get settings that "mostly" work I'll stop and let the PM do its thing.

Sadly, I'm not there yet.

And as an aside, one of the issues that I think I might have is "too many cooks". As noted above, I've been to three different health care systems with different people each time. Although my physiology "is what it is" and theoretically each of them should respond/adjust in the same way, in practice they each have their own experience levels and biases. I didn't go to Mayo for PM adjustments, it was for a round of tests (PET, cardiac MRI, ...) to evaluate whether or not I had sarcoidosis (thankfully, I do not). The PM adjustments were incidental to that.

So my plan going forward is to try and stick with a single hospital/EP/device tech to try and make progress.


by PacedNRunning - 2023-12-15 15:38:58

The top "rhythm" that you mentioned. They are checking your underlyiing rhythm. When they check this, this is without the PM on.  It's a temporary "peek" at your underlying rhythm.  It can be different every day.  I had a PM implanted for 2:1 block and during some checks, I would be in perfect sinus rhythm and other checks I would be in 2:1 block.  It's like a short electrical short that would flicker off and on.  ie Jiggle the wire and the light comes on. 

I understand the challenges with exercise settings. I have a Boston Scientific as well. I have a question. Do you need rate response on? I ask because a casual walk should not yield a HR of 140bpm.  I had these feature on and that was my experience and they turned if off.  Usually if you have heart block, the sinus node works fine.  The second thoughts are you would notice your HR drop 10-20 bpm during cycling. I experienced the same during my treadmill session. It was noted on the programmer print outs.  The intersting thing is the device tech gave me the print outs after the treadmill session. They didn't note anything wrong with my device during the treadmill session but the device tech gave me the whole printed session. He was going to toss it but offered it to me. I took it home. I kept looking at it for weeks. Finally, it jumped out at me. My PM was missing beats and causing my HR to drop 20-30bpm.  My HR would be 160bpm and then suddnetly 120bpm.  I made copies, wrote notes on it, emailed it to my EP and he agreed. We made adjustments to the PM to fill in the "dropped" beats.  

There is a setting for Boston devices called "rate smoothing" this is a setting to smooth out variation of one beat to the next.  It is programmed by percentages.  3-25%. Bascially from one beat to the next it will not allow a variation greater than the set percentage.  This was created to help with the irregularity of afib. To "smooth" things out.  When I had my treadmill session I had this feature on but it was set to 18%.  The PM worked correctly and did not allow my HR to change more than 18% from one beat to the next.  But when you are running with a HR of 160bpm with 18% rate smoothing, that's 28.8bpm difference. So my HR would drop from 160bpm to 130bpm.  Ouch! I felt that.  So we intially adjusted it to 9%.  I finally settled on 6% because it felt the smoothest. I could still feel the drop at 9%.  

My EP wasn't sure my sinus node just paused with exercise or if the device failed to sense my P waves during exercise. They commented how my P waves were smaller with exercise.  I never had issues with my sinus node prior to my PM, so I felt it's the PM not coordinating my heart due to exercise.  

I did not do an exercise treadmill session until I had my PM 7 months because they wanted to make as many adjustments prior to ensure the treadmill session was useful for the final adjustments. Our hearts respond so differently on a treadmill vs outside pavement.  You may want to do another treadmill session now that you've had your PM longer.  Also ask about rate smoothing and ensure you really need the accelorometer or perhaps lower how sensitive it is so when you are walking casually your HR isn't 140bpm.  

I hope this helps. I'm not giving medical advice, Just sharing my experience with exercise as I seem to have similar issues as you and I remember how challenging and frustrating at times I was. I did find out about rate smoothing from a really old research article in the 80's about athletes and PM' s and the use of rate smoothing. Must be something with exercise and missed beats or sudden decrease in HR. I had sent this article to my EP and that is when we turned on this setting to try it out.  I will also add you can program rate smoothign UP or Down and the percentage. At first, we tired both up and down on. It did not work.  My heart felt like a ping pong ball. :) So I only have DOWN on because I experience HR drops not HR increases.  

If you have any questions, feel free to messsage me. I enjoy sharing what I know because I feel these devices should make us feel better and provide us with what we need in order to live just as we did before our heart issues developed. 

Thanks for your reply PacedNRunning

by Aintgotrhythm - 2023-12-18 14:42:06

I've been traveling and wanted to respond to your message fully so I apologize for the delayed reply. I appreciate your response very much! I've a session scheduled with my EP and a Boston Scientific rep this coming Thursday and your reply gives me a few things to think about.

For what it's worth, I continue to have these "episodes" where my HR spikes to 140 BPM. I've not been able to discern a definitive pattern for what triggers it but a few examples:

- 3 mile walk, first part gradual uphill, very relaxed pace (32 min/mile). HR would go up to 140, I'd stop for a bit to let it settle, back to 140, stop, etc.

- Checking out of a hotel. Walked out to the car and put the luggage in then stood for a bit waiting for my wife. When she came out I walked into the lobby to turn in the keys. HR went to 140 walking back to the car - hardly a "power walk"!

- Walking down to get the mail. My driveway is about 1/4 mile long and slopes slightly downhill. Pretty much guaranteed my HR will spike to 140 walking back.

As to current settings, I do have rate response turned on and both the minute ventilation and accelerometer on. Rate smoothing is also on (turned on at last visit) at 6%. A few other pertinent settings:

Response factor: 11

Fitness level: Endurance

Vent Threshold 120 ppm

AV search interval 1024 (was 32)

This process has been very frustrating. Although I certainly think I'm special, I'm far from unique and it's baffling to me why it has been so difficult to get settings that are at least close.

In addition to the HR spikes, I'm lightheaded, "pressure" in my chest, I have what I call a "pacemaker cough". Hard to describe but I get sort of a gurgling sensation in my chest and it makes me cough.

I hope the visit on Thursday yields some results and thank you once again for taking the time to compose your lengthy and helpful reply.

How'd your appointment go?

by TwoBigWheels - 2023-12-23 20:54:58

I have similiar situation, though not as bad as yours with HR going up to my 140 with just walking. But maybe I should wear my HR monitor while working and seeing what happens...

59yr old cyclist and use power meter and HR monitior on all my rides. While on my Z2 rides (on trainer), if I start getting a little breathy (above talk test) my HR will go up to my Upper Rate (140) and stay there creating a table effect on my training software.

Part of this is due that I kept asking for more MV and as they ramped it up (9,10, 12, 14 and now 13). I noticed the big change was from 12-14,,,but didn't see a big difference when they dropped me back down to 13 (supposedly).

As far as the settings you you get those willingly? Printouts? Flash Drive? I have some settings (verbal and printout from EP but doesn't have Boston Sci terminology). It seems with my Boston Sci Techs it's Top Secret or they aren't used to people asking for them or most patients are sedentary 

Not sure if you ever seen this Boston Sci info

Settings info

by Aintgotrhythm - 2023-12-25 23:04:21

Hi TwoBigWheels,

To answer your specific question: I always (unless I forget!) ask for the settings after a session. The response has varied. Some places give them willingly (I only want the summary pages, the whole thing is about 100 pages of graphs, etc), some places won't give me a printed version but will write down what the settings are (this seems dumb to me, but whatever) and some places have refused to give them to me.

The reason I ask for them (and I explain this) is because I want to be able to document the effect that the changed settings has had. I've been back so many times attempting to get them to something I can live with that we're cycling back through settings I've had before :-(

At my last visit, I forgot to ask for the printout but my EP and I had a long discussion (with a Boston Scientific rep present) about the settings and my symptoms. Basically, where things were prior to that visit was that the settings were pretty good for cyling - my HR responded more or less as I'd expect while riding and subsequent review of HR and power data confirmed that. 

However, the other 20-22 hours of the day were not so good. My HR would periodically spike to MSR with very light activity (walking out to get the mail), pressure/fluttering sensation in my chest, "pacemaker cough" and lightheadedness.

I'd become so frustrated I sent him a message prior to the visit saying "let's talk about extraction". During the visit, we decided to change the settings so the PM is essentially off (LRL of 30, DDIR mode so I'm not V-paced if I recall correctly - I forgot to ask for the printout). 

I also told him that I'd observed that the PM responded correctly ON A BIKE TRAINER. As you probably know, the BS pacemaker has two rate response sensors: an accelerometer and a Minute Ventilation (MV) sensor. Cleary on the trainer there is no input from the accelerometer since I'm effectively "stationary" and yet the PM responds correctly - harder effort yields higher HR, easier effort results in decreased HR so we discussed trying either turning the accelerometer off or significantly damping its function e.g., "response factor" to 5, "reaction time" to 30 secs. 

I opted to try "turning it off" and have to admit it was a failed experiment. I feel pretty lousy. I'm supposed to go back sometime this week to try the second alternative (dampen the accelerometer or turn it off completely).

I'll close this very long post by saying I'm completely flummoxed. Let's ignore the long distance cycling which I'll admit is unusual among my "peers" that have PM's. I'm certain I'm not the only person on the planet with 1st degree AV block. I'm certain I'm not the only person on the planet that's essentially intrinsic (1:1) above a HR of about 108 but exhibits Wenckebach (missed V-beats) when my HR slows.

I've been back for settings changes EIGHT times now. An EP and Boston Scientific rep has been there 4 of those times. A cardiologist and BS rep was there two of the other times. The other two times were with device nurses who in my experience don't know much.

IT JUST CAN'T BE THAT HARD to find settings that work for me. As I said, I'll admit the long distance cycling is unusual but I'm even willing to turn the rate response stuff off completely and just focus on everyday settings which they seem unable to get right.

End of rant. This has been enormously frustrating and quite frankly I don't know how to proceed. As I've said elsewhere, I'd be perfectly happy to just ignore the damned thing and let it do its job if we can at least get it in the ballpark. We're not even close.

And with that, I'll bid you a Merry Christmas!

P.S. Yes, I've read the cardiocases info.

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