Question on Minute Ventilation and Cpap

Saw EP on Tuesday and he changed my PM settings.  This is the first time my settings have ever been changed.  He upped the low rate to 70bpm and turned on Rate Response and Minute Ventilation.

I have intermittent Afib but since the settings change 48 hours ago I have been in Afib a good portion of it.  My bouts of Afib are normally less than one hour.

TUES nite woke up to go to the bathroom and was in Afib and stayed in Afib until about an hour after I got up in the AM and stirred around.  Last night was not in Afib when I went to bed.  Woke up about midnight to go to bathroom and was in Afib.  When I'm in Afib I have to pee a lot so I was up multiple times during the night and was still in Afib.  Still in Afib when Ingot out of bed this AM and just finally converted about 11am to NSR.

Did some reading on the Boston Scienfific website about Minute Ventilation and it says that Minute Ventilation should be OFF if on "mechanical ventilation".  I use a Cpap at a very high setting to sleep.  Is Cpap considered a form of "mechanical ventilation"?

I sent a message to my EP through their patient portal to inform them of the extended Afib.  They responded back within an hour and told me to send a report from the PM via the bedside monitor.  Waiting on a call back.

Posing the question here to see if anyone has any experience with this.




Follow up

by Laidback1 - 2021-05-20 19:04:01

Got a call back from EP's Nurse and the PM Interrogation report does indeed show that I have been in Afib almost the entire time that they changed my settings on TUE.  (Recap:  Low Rate moved from 60 to 70bpm to try and outpace a lot of rapid atrial bursts I was having AND turned on Rate Response and Minute Ventilation). EP says there should be no correlation between the changes made and the fact that my Afib has kicked in for a long run when mine are usually are hour or less.  He says that having Minute Ventilation ON and wearing a Cpap with a high setting should not be an issue.  He said there are tens of thousands of PM patients that have the MV setting turned on and wear Cpaps.  He says I can come in and they can change everything back to the way it was - leaving that decision up to me.  With the original settings I had no energy.  I am on Tikosyn ( have been for 6 years) and he told the nurse that I'm too young for higher powered drugs like Amiodarone and he's not sure that switching me to something like Flecanaide would do any better than Tikosyn.  Needless to say I'm frustrated!  
 I just wish I could find some Dr. that would take the time to look at the big picture and help me find a balance........


I will write tomorrow

by Gemita - 2021-05-20 19:44:37

Laidback1, it is late here in the UK so I will say goodnight but I will write tomorrow since I have lots of experience with AFib + medication and sleep disorders, although not currently using APAP.  I will try to help you find that "balance"


by Laidback1 - 2021-05-20 21:51:43


YOU are an Angel.  Thank You!

Minute Ventilatoin

by AgentX86 - 2021-05-21 00:39:15

I have no experience with MV (I have a Medtronic) but I can't see how they're linked either.  Because I can't see it doesn't say much though.  Your EP can't either but that doesn't mean much either.  ;-)  I've found with AF, anything goes.

He's smart not to put you on Ameoderone.  It's dangerous stuff and the longer you're on it the higher probablility you're going to have trouble.  My EP put me on it but would do it for no more than six months at a time.  He said if I were ten to fifteen years older he would just leave me on it.  As it was, it damaged my thyroid (recovered, fortunately).  Tikosyn is the next higher on the chain, more potent than flec.  It's not without its problems and it seems it's not working either.  I'd say that you're a candidate for an ablation or even a mini-maze.  Ablatoins are less effective for those who are in persistent or permanent AF but it can work.  You'll have to find the best to do it, though.  Who does it matters.  There is a grand canyon between the best and also rans.

No, CPAP is not mechanical ventilation

by crustyg - 2021-05-21 03:24:45

The reason why the BostonSci manual warns about mechanical ventilation when MV is enabled is that the MV sensor measures both ventilation rate and also depth of each breath.  The software in the PM multiplies the two together to derive a value for Minute Ventilation and then uses that as an input to the rate response algorithm.

In general mechanical ventilators tend to be set to give a deeper breath than you would take if breathing yourself, at whatever rate they are set for.  This compensates for the lack of sighs that we normally take every so often that open up little airways that would otherwise close off, perhaps with little mucus plugs.  So mech-ventilation is likely to drive your HR up - and for many operations that's the last thing that the surgical team need.

CPAP only ensures that your upper airway stays open at the start of each breath - apart from that it doesn't increase depth of breathing nor affect breathing rate.  Yes, I know that you *can* adjust the pressure of CPAP so that it would tend to give you deeper breaths than if you didn't have it, but it shouldn't be set for that much pressure.

Also, and this is important, the MV feature works on a delta between resting ventilation and breathing harder during exercise (when it's assumed that the PM should deliver a higher HR as a proxy for more cardiac output).  The MV signal fed into RR is actually the difference between present short-term MV minus the long-term baseline from your resting MV, so unless there is a BIG difference between your depth of breath when resting and your depth of breath once you put on the CPAP mask it won't have any effect on MV into RR.

Hope that helps.

Atrial Fibrillation

by Gemita - 2021-05-21 15:23:44

Mark from your posts I believe your main concern is about Atrial Fibrillation (AF) not about your pacemaker, or your settings or your doctors who by the way sound extremely caring.  As you have discovered, AF has a will and a mind of its own and sometimes the more we throw at it (like an ablation or medication) the more it will rebel.  As you so sensitively wrote “I just wish I could find some doctor that would take the time to look at the big picture and help me find a balance . . . . “   That statement tells me so much about you.

Unfortunately AF is not a regular arrhythmia.  It can happen at any time, anywhere, for no apparent reason, can be fast or slow in speed, can hit us with short runs, longer runs, stop completely or continue indefinitely.  There is no way of knowing how it will behave or how it will affect us. Yes the peeing problem I have too when in AF and is clear evidence of the presence of an atrial tachyarrhythmia like AF since when our heart rates speed up, a hormone in the atria apparently kicks in (known as atrial natriuretic peptide hormone) and acts as a diuretic making us pee.  This apparently helps lower blood pressure and regulates the calcium and salt in the body I was told.  Clever I suppose but not easy to manage, is it.. 

The difficulty with AF is that AF can be caused by so many different health conditions, or even ageing itself, conditions that are not managed by a cardiologist or EP.  To get ahead of AF you would ideally need to see a whole range of specialists.  For example sleep apnea can be a very strong trigger for AF and sleep apnea would be treated by an experienced sleep/respiratory consultant as you well know.  Sometimes however no cause for AF is found and can be a response to an acute condition.

I can remember when I first became aware of AF, my cardiologist very kindly sent me to a consultant who could best assess “the greater picture”.  He was a former A&E (ER) consultant doctor with vast experience dealing with many acute conditions.  The first thing he did was to do a range of investigations to determine what might be causing, or fuelling my AF.  He looked a little deeper into the usual causes like thyroid problems, infection, diabetes, auto immune inflammatory conditions, autonomic conditions, cardiomyopathy, scarring of heart tissue, sleep apnea, high blood pressure, electrolyte abnormalities, anaemia, ischaemia, abnormal heart valves, past/present medication, lifestyle habits (alcohol, caffeine, tobacco, stress) and so on.  He explained “get any health condition effectively treated and it could be all the treatment you need to control your AF”. 

It sounds as though you need such a work up Mark to make sure all possible causes for your AF have been identified and that you can feel reassured you are taking the right path.

A Balanced approach:

So what is the right approach for you?  This clearly needs assessing but I have found the best approach is sometimes to do as little as possible, just enough to keep my AF under control, to prevent it from progressing to a more permanent state but without hitting it too hard. 

When I first got my pacemaker (2018) I found that I was able to safely reduce my medication as a result of pacing.  Initially, they found my high doses of Flecainide with pacing seemed to cause worsening arrhythmias, a “pro arrhythmic effect”, so they reduced both Flecainide and Digoxin (now stopped).  They have offered Amiodarone, a pulmonary vein isolation ablation or an AV Node ablation at some stage in the future, if required.  I am confident though my pacemaker is helping to address a pausing, falling heart rate which was clearly triggering many arrhythmias.  A higher steadier heart rate of 70 bpm day and night has made a tremendous difference and was really all the treatment I required.  AF still continues intermittently but with Bisoprolol it is well controlled both in duration, frequency and heart rate, so I do not need to do anything more at the moment.

I do not have technical knowledge of pacemaker settings and how they might be able to help you with your current symptoms but I know that in the presence of an arrhythmia like AF, getting pacemaker settings tuned in correctly may be more difficult.  In my opinion it might be easier to try to control the AF first before making too many changes to settings.  

Looking at your history Mark I can see you have had two ablations and AF has been going on for some years.  Clearly the ablations haven’t been completely successful, although we know a “total” cure for AF is not possible.  The best we can hope for is a long period of respite from AF following a successful ablation. 

I see you are on Tikosyn, a heavy weight med in my opinion (far heavier than Flecainide).  Most definitely we both needed our pacemakers but do we need any further treatment in the future for our AF.  That is the real question?  Our journeys differ in that you have had two ablations and I none.  I chose to go down the pacemaker route immediately because it seemed the best approach for me at the time.

In your shoes, I would be asking myself and/or your doctors the following questions and then base any treatment plan on your answers:

.  What percentage time am I in AF?  If only minimal, consider:

.  How symptomatic am I when in AF and what are my symptoms?  Do symptoms warrant immediate treatment (like stronger meds or another ablation?)

.  How high does my heart rate go when in AF?  Is my heart rate controlled by medication?

.  What side effects do I get from Tikosyn or any other medication?  Are the side effects worse than the symptoms from AF alone?

.  Are there any underlying health conditions present causing my continued AF?

Heart rate control (usually a beta blocker or calcium channel blocker) and anticoagulation to protect from an AF related stroke (if we have risk factors) are the two most important medications we may be asked to take.  Otherwise, providing AF is not adversely affecting your quality of life, you may be told you can leave well alone.  It is a treatment option and works for some Mark.  Sometimes hitting AF with ever increasing higher doses of meds or other treatment will just not work and may even make your situation worse.  I understand all about AF begets AF and remodelling of heart tissue but finding the right balance is so important too and less treatment is also a valid option providing it is safe for you.  Perhaps try out the benefits of a higher 70 bpm minimum lower rate first or give yourself more time with pacing support before you do anything else.  It may take some getting used to but it has worked well for me, cutting the number of my AF episodes substantially according to my data.  Rate Response/Minute Ventilation settings changes will be trial and error until your settings have been optimised for you.

I see crustyg and AgentX86 have given you good advice.  I just wanted to reassure you that bursts of AF maybe acceptable providing symptoms can be well controlled.  AF, following any intervention and that could include pacemaker setting changes may not be significant or confirmation of a worsening situation.  It may settle down.  What would be significant would be if your AF were to continue beyond the several hours period or didn’t stop at all without intervention (say without a cardio version) and your heart rates were high and not under control.  Persistent AF with high heart rates and worsening symptoms (breathlessness, chest pain, dizziness, extreme fatigue/weakness) would be a cause for concern and would require immediate treatment.  Are you at this stage Mark?

Finally, is your sleep apnea under good control.  If not, this could be causing increased AF.  Have you recently had a full in hospital sleep study done just to confirm that all is well?  Your comments that you were getting episodes of AF at night but returned to NSR on getting up might point to a problem and a sleep study might be valuable to confirm what is going on.  

You will get better Mark but you have to have confidence to leave well alone sometimes, especially if your symptoms are not too troublesome or seriously affect your quality of life.  Clearly from your comments you still need to find “the appropriate level of control for your AF which is right for you” and this is why I would suggest you go back to your doctors and ask perhaps for a complete review of all your medication, answers to the questions I have suggested above, a referral for further assessment for any potential health conditions causing your AF.  I will close now but wish you well

Thanks to All & Update

by Laidback1 - 2021-05-21 17:53:43

Lengthy but summarizes my history:
First of all, thank you AgentX and Crusty.  Great information and provides me more knowledge to fully understand my PM and helps me with expectation setting.

Gemita, thank you for your well thought out and caring guidance.  You provided me so much to think about and I am definitely going to follow up with my General Practitioner, Cardiologist and EP with the questions and strategies that you outlined.

Over the years my expectations of controlling Afib have changed.  My initial push was "I am going to beat this thing into oblivion" when I should have been taking a more thoughtful approach and took time to address root causes.  A little history, the first cardiologist that I worked with when I developed Afib was "gung ho" as well and immediately put me on Amiodarone (I was 48).  
I took Amiodarone for 3 years.  For the first 2 1/2 years it worked great.  No Afib, no blood thinners feeling great.  I had follow ups with the Cardiologist every 6 months and he did an EKG, took NO blood work and said you're good to go.  At some point, my Afib started coming back intermittently and it would just last an hour or so.  He put a holter monitor on me for a week and the report showed Afib and all sorts of other short atrial arrhythmias.  He put me on Warfarin, kept me on Amiodarone, still did no lab work and said "well that's just Afib live with it".  It didn't take long before I started really having troubles and he sent me to an EP.  The EP was "gung ho" as well and said you're too young for Amiodarone, I'm going to put you in the hospital for 3 days and start Tikosyn and let's do an ablation.  That's what we did.  He ran all sorts of tests before hand but did NOT do a full blood work up.  Tikosyn on board and then we did the ablation.    
I stayed in NSR for one hour and then was back where I started.  Afib and other assorted "unclassified" atrial arrhythmias......

EP said let's get thru the "blanking period" and see what happens.  So, I really struggled for 3 months.  No change, feeling awful and he says we need to do a cardioversion.  Went to the hospital.  He did two cardioversions and in both cases I was immediately in Afib.  At that point he orders lab work and it turns out that I was significantly hyperthyroid!!!!   So, three years on Amiodarone with no lab work to check things damaged my thyroid......   I learned a valuable lesson and I hope the Cardiologist and EP did as well!  The EP did immediately refer me to a top notch Thyroid doc that was extremely caring and thorough.  He took over and six months later my thyroid had healed, my arrhythmias stopped and I felt good again.

Needless to say I found a different Cardiologist and EP and took my time reasearching them and talking to patients.  A couple of years later my Afib kicked back up and my new team felt like I might need a "touch up" ablation.  It worked for a few years but did come back but it was "livable".  It was something that occurred monthly or so but the rate was well controlled and it converted on it's own usually in less than an hour.

Fast forward a couple of years and I started having pauses when I was converting from Afib back to NSR.  It made me a little dizzy but was still only happening once every couple of months or so.... until Jan 31st of this year when my wife found me on the driveway passed out.  I came to quickly but I was having long pauses and it was very symptomatic.  ER doc called in Cardiologist and he said I needed a PM ASAP.  My EP was unavailable so an Interventional Cardiologist did the implant....

Update from Today:  EP's nurse called and said to come in that they wanted to look at things.  They turned off Minute Ventilation and left Rate Response on and had me take a brisk walk.  Got back and they interrogated and my Heart Rate went from my base rate of 70bpm to 82bpm.  They had me rest for a few minutes, cut OFF Rate Response and had me take another brisk walk (same distance, same speed).  Interrogated and my Heart rate went from 70bpm to 81bpm on its own.  Said you don't need rate response but that we would watch it as I started doing more strenuous activity to make sure.  So, my base rate stays set at 70bpm to see if the higher rate will pace me out of the bursts of arrhythmias that I am having.  RR and MV are OFF.

I have a scheduled follow up in 3 weeks but if something occurs before then I am supposed to call.  And, I converted back to NSR!

So Gemita, I have learned the hard way..........  Balance is where it's at.  I have an appointment with my GP in 10 days to do full blood work up.  We will also be discussing a referral for a sleep study to make all is well there.  In addition, I will ask for a complete review of all my medications to make sure there are no issues there.  Hopefully he will do it or I will find another GP.  

I am now in "the camp" of get Afib to a state that I can live with and leave well enough alone.  The last couple of days of extended, symptomatic Afib just did not match what I'd grown accustomed to. After today's visit with the EP, I am hopeful that we can find that balance again....

Thanks for taking the time to offer caring and help!



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