Is anyone paced on the AAIsafeR pacing mode?


My heart block was intermittent grade 2 at implant with no sinus node issues. However my PR interval was quite long. It may always have been we will never know.

I am anticipating that at my first appointment today that if I am spending large amounts of time without grade 2 heart block I may still be ventricular pacing due to the longer (not unsafe) PR interval. 

I read the following in a paper,

"The most sophisticated approach yet available for atrial pacing with a dual chamber pacemaker is a pacing scheme implemented in new ELA Medical pacemakers. Called AAIsafeR, it provides true atrial inhibited (AAI) or atrial inhibited, rate-modulated (AAIR) pacing until a pause of two or three seconds with non-conducted atrial beats or persistent 2:1 AV block, indicating the onset of AV block and the need to switch to mode DDDR pacing. Search algorithms allow the pacemaker to return to AAIR pacing even when there is a substantial first-degree AV block, but too frequent switching causes permanent dual chamber pacing"

Is this something I should be pushing for if it turns out I very rarely need ventricular pacing due to intermittent grade 2 block but I am still being paced a large proportion of time due to the longer PR interval?

Has anyone experienced this pacing mode and had success with it?


AAIR mode

by Gemita - 2020-12-21 07:01:31

Hi John,

I have dual chamber pacing AAIR<=>DDDR.  I am pacing mainly in AAIR mode (atrial pacing, atrial sensing, inhibited response, rate adaptive) when I am in normal sinus rhythm which then switches to a non atrial tracking mode (DDIR) when I develop an arrhythmia like Atrial Fibrillation, so as not to track the mayhem in the atria, returning to AAIR mode when the fast atrial tachyarrhythmia ends.

AAIR pacing mode seems to work well for me and I am generally happy with it, although with frequent arrhythmias I am constantly changing modes at times and this can drive me crazy.  My % ventricular pacing is well under control though which is excellent.  AAIR mode seems to be ideally for patients with Sick Sinus Syndrome, rather than AV block but I might be mistaken?  My question to your EP/Cardiologist would be . . . "what programmes are set up in my pacemaker to help reduce unnecessary ventricular pacing" rather than asking him specifically about AAIR


by AgentX86 - 2020-12-21 12:47:57

From what I can understand this is similar to what Gemita has but it's different in that it's intended for those with SSS and first or second degree (and intermittent 3rd degree, one would suppose) AV block.  It's basically AAIR mode until it detects an AV block for some period of time, then switches to DDDR mode to pick up the ventricular pacing.  It switches back to AAIR when it detects the normal AV pacing (how it does this is left up to the interested student).  The idea is to reduce ventricular pacing, thus cardiomyopathy caused by RV pacing.  It's named as it is because it's AAIR pacing but is safer than DDDR for those who can use it.


by quikjraw - 2020-12-21 15:35:01

Well would you believe it without really saying much I was immediately changed from DDD mode today to AAI-DDD mode. Reading your posts Gemita and AgentX86 that may work well for me as as the AAIR-DDDR does for you Gemita.

I was atrial pacing 23% of the time and ventricular pacing 46%. I was very suprrised at that. I did not expect the ventricular to be so high. I think the 23% atrial pacing is purely due to the fact I was set at a minimum 60ppm at rest or asleep. They have now lowered this to 40 without even a discussion but if it helps me sleep then great.

I did not get to really discuss the 46% ventricular pacing, they did mention that this is highly likely to be associated with the long PR interval I have but I suppose I will have to wait now for 12 months to find out more as that is my next appointment.

I must admit it was a very rushed appointment indeed considering it was my first.  I would have been in there 5 mins at most if I hadn't asked more questions. 

It was not really the time to be discussing my originally diagnosis as others had said in the my previous post.

Now I am free to start exercising they said so hopefully I am now onto the next stage of my return to normality......well some kind of normality!

You did well to get some answers

by Gemita - 2020-12-21 16:20:47

Hi John,

Thank you for the update.  You may be feeling somewhat disappointed with the rushed nature of your appointment (we have all been there!!) but I really think you did extremely well to ask so many questions and to get a few things sorted.  I didn't fare so well on my first appointment with the technicians, so well done you.  

I am glad you have got your lower rate lowered and hopefully you will get a better night's sleep from tonight.  I am glad too that you are set AAI-DDD.  Without an arrhythmia you should have fewer mode switches than I am getting and pacing will hopefully be reduced in the right ventricle - block permitting !!  Did you manage to ask whether you could get a copy of your data downloads today?  If not, remember you can always get further information by asking for access to your records.  I am currently doing this.  It is taking longer because of COVID-19.

Finally, did they mention whether you would be seeing your EP/Cardiologist at any stage to discuss your results (and to ask all those additional questions),  although if all is well, he may not need to see you.  Hopefully you will get a copy of today's summary report, either through your clinic or GP if you ask.  If you do not get a follow up appointment with your EP/Cardiologist, you could always write to him/her with your questions.  I do this often with my EP and he always responds.

Sounds cool

by crustyg - 2020-12-21 17:39:19

But then marketing blurb should always make you want to reach for what they are dangling.

It sounds like a really clever feature - cleverer than my PM, and a nice way to avoid *all* unncessary vent pacing, which is particularly important if you have an apical RV lead, IMHO.

Please do let us know how it's gone after your next follow-up appt: in theory what you have now sounds perfect.  But theory and implementation aren't always a perfect match.  I would have gone for it if needed, but so far, I don't.

Glad to hear you're looking forward to getting on with your life.

Season's Greetings.

Long PR

by AgentX86 - 2020-12-21 22:07:24

Yes,, a long P-R interval will naturally raise the VP percentage because that's what your pacemaker does.  Whether from the pacemaker or the SI node, the atrial signal (P-wave)  propogates to the AV node, delayed some, then to the ventricals (you see the large "QRS complex"on the EKG).  So the P-R interval is the time between the atria firing and the ventricles (the max is the "R" wave).  If this is long, the pacemaker doesn't sense the QRS after some time, so inserts its own.

good points

by quikjraw - 2020-12-22 04:43:29

Morning Gemita, I did not ask about the data downloads and I had to stop them in their tracks to right down the pacing percentages they were not going to tell me them. I overheard them talking about the mode switch and because I had done some homework I knew roughly what was going on so I was able to aks them to stop and clarify the mode change they had just made.

How do I request a summary of the settings I have? Is it through my GP or directly to the hospital? As that sounds a great idea. I would like to know if they have dropped the lower heart rate at night only or at all times.

I really though the EP/Cardiologist was going to be present as she did suggest that she wanted a follow up to test for genetic issues. I also would have thought it would have been nice to at least talk about the current state of my block. Clearly the numbers do not tell you that especially with a prolonged PR interval.

I will do thanks CrustyG

AGENTX86 Do you know how long AAI mode waits for an intrinsic ventricular beat or is it configurable? It would be even better if it waits longer than the DDD mode as I have read time and time again a long PR is not an issue in itself so I would rather not be paced simply for this issue if my grade 2 heart block is not present for any length of time.

Morning John

by Gemita - 2020-12-22 06:44:05

Hope you slept better.  To answer your questions.  You have many options:


Data Downloads - I applied by email/online form to my hospital’s Information Governance Office (check online to see where to apply in your hospital), requesting an electronic copy of all my downloaded data from my last pacemaker interrogation check.  I applied on an online Form for “Subject Access Request under the Data Protection Act 2018 or Access to Health Records Act 1990”.  They are required by law to give you this information within a time frame, but with COVID-19 my hospital has not yet provided me with FULL access, only a summary sheet of the main settings. 


For the odd question or two like is your heart rate set lower at night only, you could (1) ring your pacemaker clinic and check (2) if you wake in the night, check what your heart rate is and then compare with the rate during the day - do this over a few days to get a more accurate assessment (3) wait for a Summary Sheet to be sent to your GP of the results of your latest pacemaker check, which should include any changes made and confirmation of % pacing, any events, lead, battery integrity and other essential details like diagnosis/indications for pacing.  Then ask for a copy from your GP.  They should receive this over the next few weeks.


I would write to EP/Cardiologist with any questions you may still have, but keeping to essential need to know ones!  BUT remember, the current state of your block is a changing situation and only time will tell how this might progress.  In the meantime, enjoy your life.  You have a pacemaker now to keep you safe whatever your heart may decide to do.


Your settings for your AAI mode will be personally set for you, which is why you need to get a copy of that data to see what has been set up.  These settings can be changed/optimised to suit you better ONCE THEY KNOW how well you are responding to this mode of pacing.  It is a work in PROGRESS John, so please be patient.  For example my AAIR mode switches when an arrhythmia is detected above a certain bpm rate and after a certain number of beats.  This instruction has been programmed in my settings and is unique for me.  Mode Switch can be made less or more sensitive, so they can fine tune all settings to get it right for you.  

ACTION PLAN:  Enjoy Christmas;  Apply for your full Data downloads and/or get Summary Pacemaker check report from GP;  Read your pacemaker manual (to understand about settings);  Write down a few need to know questions and send in a nice letter to your EP/Cardiologist, telling him how grateful you are for everything they have done so far, but wanting to know just a little more . . . !  Any such letter can be a subject for another post if you wish.  How does that all sound?

Literally the perfect 4 step plan

by quikjraw - 2020-12-22 08:49:16

Gemita that is such a perfect plan I am going to simply cut and paste it and stick it in my google keep list.

Thank you very much.

I did not sleep any better last night but maybe I will have to get used to the new set up.

Have a great Christmas and a Happy New Year.


How Long?

by AgentX86 - 2020-12-22 13:29:13

From what I've read, it waits for five missed A/V beats to switch to DDDR mode.   I'm sure the number of missed beats before a switch is configurable. I have no idea how/when it knows that the AV node is functioning again so that it can revert back to AAIR.

I have the same

by PacedNRunning - 2020-12-23 02:40:12

Hi. I use to have intermittent 2:1 exercise induced block. The goal was always to only pace me for exercise and minimally pace me when not exercising. Because of my settings i did pace unnecessarily but I had to in order to give me what I needed during exercise. The best way to handle this is to have dynamic AV delay. It's a range that will pace you based on HR.  As our heart rate increases our PR interval or AV delay shortens. So they give you an exercise range and a resting range.  This should limit pacing. The other way is AV search or hysteresis. It will check XXX amount of cycles to search for intrinsic beats. If it senses intrinsic beats, it will stop pacing and allow your heart to work when it can.  The mode switches you talked about earlier is only recommended for Sick sinus syndrome of First degree block.  If you have 2nd degree or 3rd degree intermittent, you don't want to limit pacing in that manner.    I started with intermittent block as I mentioned before, paced about 50% of the time, I probably needed about 10% for exercise. Now I'm pacing at 100% on demand because now my block is no longer intermittent but persistent. Part of me thinks becaus we limited pacing it made my heart weaker vs giving my AV node a break.  That's my own theory.  So that mode switch may make you AV node work harder.  I would call and get a report of your last check up.  I kept track of my setting changes, how each one felt and my pacing.  

very interesting

by quikjraw - 2020-12-23 04:38:56

Thanks PacedNRunning,

I rang them back after Gemita's post and got a little more information. They have actually removed the 500ms limit so that the heart is using intrinsic beating unless a certain number of beats are missed, the person on the phone was not able to tell me how many beats. The mode apparently was always set to AAI-DDD even after implantation so I am confused why they said they had changed it. 

I did not appreciate (but now it is obvious when I think about it) that the AV delay reduces when exercising. You mention you have exercise induced block I will now have to see if I have the same now I can start getting my heart beat up a bit more than just walking.

I've had it in my head that the 2nd degree block only happens in me when resting. I am basing this on the fact I was performing running and road cycling prior to the implant to a high level (for my age) so I assumed I could not have had any sort of block during exercise but maybe this is not true. 

I can see that we all need personal fine tuning. 

How much did your running performance change after you had the PM fitted and settled on the settings? Have you managed to get back to a near pre-PM pace?


Just random thoughts

by Gemita - 2020-12-23 07:30:05

John, really interesting to hear PacedNRunning's contribution.  She certainly knows about pacing.  It was interesting too to hear that you were always in AAI-DDD.  

You see how important it is for all of us to keep asking questions to find out what is set up in order to optimise our settings.  I feel certain if settings are fine tuned, it will make such a difference to our quality of life and whatever type of pacemaker we may have, I believe it can be manipulated/optimised to suit us individually, but it requires patience and effort on our part and a willing technician/EP to listen to us and help us to achieve our goals.  

But remember, the heart's electrical system is constantly changing depending on other health conditions, on any meds we may take, on our mood/emotions, on lifestyle, on exercise, at rest, trauma to the body causing stress and so on and it is never a static situation, so we may have to re-visit our settings from time to time and change them.  No wonder EPs/Cardiologists/technicians are kept so busy.

Is your heart rate set at 40 bpm day and night, or only at night? Has it improved your sleep?  I wonder whether a lowering of your heart rate will adversely affect your block?  Would be interested to get PacedNRunning's opinion when she wakes up ?  I know when I had falling heart rates in the low 40s and below, it often seemed to trigger worsening episodes of bundle branch blocks (both left and right), together with Atrial Fibrillation.  I wonder therefore whether 40 bpm might be too low a setting for you John, but only time will tell


New lower heart rate

by quikjraw - 2020-12-23 09:04:56

That was something else I asked them to clarify Gemita and yes it is set at a minimum of 40 at all times.

My simple view and very limited experience so far is why would I need any pacing at all from the atria? When my heart rate dropped to about 30 in hospital this was not an atrial beat of 30 as I believe my p waves were beating at a normal level, it was the ventricles not beating (the worse was 2:1 block) that effectively lowered the measured heart rate to 30. 

I suppose if my ventricles were beating 1:1 I would have had a measured heart rate of 60?

When your heart rate dropped to 40 would your ventricles still have been paced or was this prior to your PM?



Lower heart rate

by Gemita - 2020-12-23 12:37:03


You clearly do not have complete heart block from your percentage pacing figures, but when you are in block, can you really be so sure that your own SA node is always firing at a rate sufficient to power your ventricles adequately, the main pumping chambers of your heart?  That would be my main concern at a minimum rate setting of 40 bpm. 

If supposing your SA rate is low when a block occurs, this will be the rate transmitted to your ventricles and if for example you are exercising at the time and needing more support for additional energy requirements, you would not get support from a low rate in the 40s bpm range for example and you might get breathless and struggle to maintain a good level of activity. 

A minimum rate of 40 bpm I would argue is too low.  I have seen members here with incomplete/complete heart block set at something like 50-60 bpm minimum, but not 40 bpm.  This seems too low a setting and would not give a safety net if your own SA rate were to be low when a block occurred.

I have Sick Sinus Syndrome (Tachy/Brady Syndrome), so a completely different condition.  I also have arrhythmias and intermittent bundle branch blocks so a complex picture.  Prior to my pacemaker John, during a bradycardia episode I would frequently come over cold, breathless, with sudden plummeting heart rate and blood pressure, down to something like 70/40/39 during the day and those values were clearly not sufficient for my needs.  At night my heart rate would fall below 30 bpm to mid 20 bpm and I would wake fighting for air.  The lower rates would often trigger my arrhythmias and then I would experience sudden, surging heart rates and blood pressure values of around 190/120 with a ventricular heart rate sometimes peaking briefly at over 300 bpm, before dropping back rapidly, so you can imagine I was extremely symptomatic and unstable during these episodes.

Before my pacemaker, my heart rate frequently dropped to below 30 bpm at night for long periods (this was my ventricular rate value) which clearly was not enough to support me.  During the day it frequently dropped to the low 40s bpm for lengthy periods too and I felt even worse as I tried to carry out my daily activities.  I was barely functioning without my pacemaker and my awful arrhythmias just added to my distress.  That has all changed now and my quality of life is much improved with a constant setting day and night of 70 bpm.  I feel warmer, more alert and can exercise without difficulty.  My arrhythmias, heart rate and blood pressure are stable most of the time.

I am still waiting for my detailed data settings (requested mid October) since I want to see what has been set up Mode Switch-wise, since I feel settings may need to be adjusted to reduce frequency of mode switches and save battery.  I hope that helps



I'm glad you saw such an improvement

by quikjraw - 2020-12-27 10:33:34

Merry Christmas Gemita!

It looks like you saw a massive improvement after your Pacemaker was fitted. You must have felt like a new person!

For me as you can imagine I've gone from feeling extremely fit and healthy to less so with a few complications thrown in 

I can see what you explain about the lower rate setting now. 40 does sound low. As it happens for reasons I can't get my head around I'm still pacing at just under 60 during sleep. I've also had another couple of sustained higher heart rates when simply sat down. 

My monitor arrived Christmas Eve and I'm now all set up so hopefully that will communication simpler 




by PacedNRunning - 2020-12-31 01:03:21

Hi. So to your answer your question to me. Am I back to prePM running pace. No. 😂. Sorry. But the key is I can still run and do all the things I did before. Since I paced 100% in my V lead with exercise that took some time to get use to and tweak. It basically started pacing me 100% when my HR reached 100bpm up to my max of 185bpm. So in the beginning it kicked in too slow and the first 2 mins of exercise I felt awful. Hard to breath etc. just like normal running except a little more exaggerated. You know when you run or exert yourself the first few mins are hard and then things plateau and you feel fine. Well like that except moderately harder. Once my pacemaker paced faster and more physiological for exercise I felt much better. So I would push through each run until I hit my plateau. Being paced wirh exercise in that bottom ventricle at high rates extended periods made me tired. It's way better now but the first year it made me tired. So I would cut back the amount of time I ran to 30 mins and then built up from there. So just listen to your body. Scale back some if you have too and then increase back to where you want after you give your body/heart time to adjust. Now that I'm pacing 100% my settings are as short as they can be, I feel like a normal person exercising. So it's a give and take. I would totally take back intermittent pacing over 100% pacing. But it's what my heart needs so I have no choice. You may have to do a treadmill programming session with your team to get to dialed in good. 

to explain the algorithms to minimize pacing. You typically have to miss 2 beats out of 10 for it to start pacing you. So basically 2 dropped beats. I will say for me. That algorithm did not work for exercise because every time it checked I was in block and it felt like someone punched me in my stomach twice every 2 minutes! Not ideal. After a while that catches up to you hemodynamically. 

as far as your minimum setting. I was at 45 at implant. the following morning my doctor saw I paced all night at 45, so he lowered it to 40. Well my heart didn't like 40, I went into junctional rhythm. So we put it to 60bpm. 60 bpm was too much for me since my PM is not for bradycardia. So it's been at 45 for quite sometime. I will say we did have to bump me to 50bpm bc it made the settings work better. Not sure why but overall 50bpm feels better. 

the reason you pace under 60 is because the bottom lead will pace at any heart rate. It's not looking for HR but block or slow PR interval. So the top lead will pace if you drop below 40 but the bottom lead will pace 40- up to your max rate. Hope that makes sense. 

I hope answered or clarified some information 

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