New settings following exercise stress test

Hello All,

Well today I had my exercise stress test and download.

I was hoping my block was not present during exercise but unfortunately it was. The AAI-DDD mode was not really working and probably explained some of my symptoms. In fact even though AAI-DDD was suppose to minimise pacing (it actually only intervenes if 2 or more Ventricular beats are missed in 4 atrial beats) I was still at 80% pacing.

I must have been constantly switching between AAI and DDD. I suspect that was not ideal. 

My upper track rate before the test was 150bpm, and I surpised to see that they could not get my heart rate to go above 150bpm due to the AAI mode and wenkebach rates. My upper track has now been moved to 180bpm. They said that was the maximum they could do.

They then did a lot of analysis and adjustments and right in front of my eyes my heart rate jumped to over 170bpm. It did feel easier at that stage. They had to jump a few steps on the Bruce Protocol to get my heart rate higher.

I am now in DDD mode with rate adaptive AV delay so I suspect I will now be paced 100% of the time. This aspect is disappointing but then they did try to minimise the pacing as best they could and it was clearly not working. 

I have another month of personal testing to see if exercise and daily activities are better and they will look again.

All the best



Hi, quikjraw. I

by KatieG - 2021-04-26 15:29:07

I wonder if you could explain something that's been mystifying me since I had my PM fitted, just over a week ago? It says on my Pacemaker card that it's set to DDD. I was still groggy when I went home so didn't think to ask the physiologist what that means. Also, there only seems to be a lower heart rate set, no upper one mentioned. Can you shed any light on why this might be? I'm in the UK, so not sure if things are done a bit differently here! Hope you're doing well. 


Progress ?

by Gemita - 2021-04-26 15:29:15


Thank you for the update.  For me you are making real progress and getting that test so quickly was most impressive.  

If your quality of life improves and you can reach your full exercise potential, that would be such a leap forward.  I wouldn’t worry too much about your pacing percentages right now.  If you are in block your obviously need pacing support and to deny yourself this would not be wise, especially since you have clearly been struggling with your settings.  How you feel now is perhaps more important than worrying about how you might feel in the future and if you feel good now, chances are that you will continue to make progress, continue to build up your strength, improve your blood flow and lower your risk of heart disease in any event. 

Let us see what you are able to achieve over the next month of personal testing.  Keep a diary of any difficult symptoms so that they can pinpoint what might be happening or if any of your settings need adjusting.  That must have felt so good when your heart rate jumped to over 170 bpm during exercise.  Did you notice any discomfort when it suddenly increased, or did you just feel a sense of “release/freedom” as though you were taking off at last? 

Oh what an experience.  Who was there?  A technician and a Medtronic representative?  And did you get to ask some questions and were they patient and helpful?  I hope your new settings work well for you


by AgentX86 - 2021-04-26 17:25:00

Pacemaker modes/codes tell us how the pacemaker is programmed to operate.

The first character tells which chamber is in being paced (Atria, Ventricle, or Dual)

The second tells us how pulses are being sensed. That is, where the pacing, if any, is coming from. (Atria, Ventricle, Dual, or O=no sensing),

The third letter says what the pacemaker does with a sensed beat (I=Inhibit pacing, T=trigger pacing, O= do  nothing).

The fourth character indicates rate response (blank=no rate response, R= rate response set on).

The fifth character, if there, indicates multiple chambers paced O= none-same as blank, Atrium, Ventricle, Dual)

DDD is the most common setting.  Both the atrium and ventricles are sensed and if everything is working properly, the pacemaker does nothing. If the sinus node skips a beat, the atrium is paced. If a programmed a.out of time passes and the signal hasn't made it to the ventricles, a pacing signal is supplied to the ventrical(s).

Thanks Therese

by quikjraw - 2021-04-27 12:24:20

I think there was a Cardiac Nurse and an EP technician.

It would appear I had Wenkeback during exercise which meant that some beats were being lost in the refractory period (i think that is right) I was at quite an incline and pace and found it very hard at one point (I thought to myself I would not be able to continue for much longer). Once the settings were changed I really did notice a difference it was simply that it felt easier.

I asked a few questions and I was provided with a new settings summary which I can share if you are interested as it shows histograms of pre december and post december settings.

I will certainly keep you posted on my progress.

Yes please John

by Gemita - 2021-04-27 16:20:41

Would be interested to see new settings summary sheets compared with your previous ones.  Disappointingly I am still waiting to receive my full pacemaker data I originally requested last October.  I emailed my EP's secretary about a month ago who is usually so good at replying, but absolutely nothing has been received (other than the summary sheets you have seen). Perhaps I am asking too much (the full download).  I may try once more and then give up John.  

So you were really pushed on the Treadmill.  In many respects, it was helpful that you were in block when you were being tested.  At least they were able to see you when you were struggling and they were able to adjust your settings to meet your requirements when you most needed it.  I hope your higher upper rate makes a difference and you don't get held back as previously.  Have you tested out your new settings? It was lovely down here today, so hopefully you had some fair weather too.

Hope you get some answers on Paced AV delay setting.  No doubt you have checked this site and online?  I am sure it will be an "individual" adjustment for best results, although I expect there will be an "acceptable range" in general.  I would add to your latest post, your new Paced AV delay setting in case it helps other members respond to your message.  I do not have block but you know mine is (paced) 180 (ms) and (sensed) 150 (ms)

Upper rate limits.

by asully - 2021-04-27 21:49:07

I am so glad you were able to get them to make this adjustment so fast, it took me 5 years and three devices later to have mine pushed to 175 from the original 140.  I have CHB, and back when I was able to exercise, the upper limit would trigger mode switch into pacemaker mediated weinkebach which was awful.  I know many others have had better results once they get this upper rate limit raised I hope it works well for you too!

I would love too see your settings

by PacedNRunning - 2021-04-29 03:16:50

NIce treadmill session! Sounds like a good one and finally  able to see what your experiencing. They had that mode switch for me AAI-DDD mode but it was called AV Search. AWful with exercise. The reason it was awful was because it switches back and forth and you have to miss 2 beat for it to switch to DDD pacing.  When your exercising these cycles happen much faster because your HR is faster. So you should feel better with that off.  I had mine off early on after implant.  Not tolerable.  You shouldn't experience wenckbach at all until you go over your MAX track. they would have to adjust your PVARP to fix that. The reason they couldn't get your HR Over 150bpm is because the pacemaker is told to only pace to your max track rate which is 150 or was 150bpm.  Especially if you have HB this max track matters 100%.  If you didn't have block, you could easily go over 150bpm if your own heart could do it.  So your capped at whatever they set it at with HB.  They raised mine to 185bpm so I will never reach it.  Again, you should have 1:1 pacing up to your max of 180bpm then after 180bpm you wenckeback and then 2:1 block after that. So they should be far enough away you never reach it.  You may not pace 100% if they set up your PM to allow your own heart to work when it can then you will still beat the PM if your heart can do it.  So you never know. :). 

I'm very happy for you! It's such a noticeable difference when they get it dialed in right. Try not to focus on how much your pacing or limit pacing. Go with what you feel and how it feels.  My goal was limit pacing also in the beginning and you can only limit so much. :) 

I will post my settings on the gallery

by quikjraw - 2021-04-29 04:26:26

Thank you both for your encouraging comments.

I'm interested in understanding that I potentially spent a decent proportion of my life with a longer than normal PR interval (450ms at lower heart rates) unless of course this occurred out of the blue last year which seems unlikely looking at studies. This being the case I am wondering if it is a good idea for my paced AV time to be quite a bit different from my own PR interval. I suppose I will find out when I start running again, though in the last week I have lot's of joint swelling that I need to sort first, it's like spinning plates at the minute.

Again, assuming I had this longer PR interval last year i was running at very high level for my age (I was getting close to a 5 minute mile in June)  so that PR interval was not only not causing me problems but was working extremely well during exercise.

PacedNRunning, May I ask  what your Paced and Sensed AV delays are please? Also When you were in AAI-DDD did you also notice any symptoms at lower heart rate acivities? I had consistent dizziness whilst doing DIY a few weeks back every time I stood up from measuring the wood I was cutting. It happened every time over a weekend, probably about 50 times.


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I've seen many posts about people being concerned about exercise after having a device so thought I would let you know that yesterday I raced my first marathon since having my pacemaker fitted in fall 2004.