Rate Response settings in DDD mode

I have a dual lead Medtronic Azure XT PM which is currently set in DDD (only). My SA node is working fine and is driving the AV node. We are currently trying to optimize the settings for my extracurricular activities.

The tech was saying that when the PM is in DDD mode, none of the rate response settings matter EVEN IF the Rate Profile Optimizatoin setting is set to ON. I cannot find anything in the manuals that supports this statement. I was wondering if anyone has any data that can provide some clarity.



I think he's correct.

by crustyg - 2022-03-03 19:36:37

I don't know the Medtronic kit very well, but a quick look at the Ref manual suggests that the EP-tech is correct: section 4.6.2 mentions that Rate Responsive pacing is only effective if the PM is currently in DDIR, and not when the pacing mode is DDD.  The box can be configured to use MVP and switch automatically between DDIR and DDD.  Sounds ideal for someone with a working and responsive SA-node - but if it's working normally I'm not sure that I understand why you need optimisation (but I'm only skimming on the surface here).

Do you have your settings and reports from your last EP-tech session?  It's always worth taking a thumb-drive with you and asking for a copy of everything...  Otherwise it's likely that you'll have to make a more formal approach for your medical records and stipulate that this must include ALL PM related data, reports, settings etc.  It won't be quick.

Final Parameters listing

by SNORTINGDONKEY - 2022-03-04 18:14:24


In my case, my AV node is paced 100% of the time due to a complete heart block.

Here are the settings from the EP session from yesterday.


Mode = DDD

Mode Switch = 182 bpm



Lower Rate = 60 bpm

Upper Tracking Rate = 165 bpm

Upper Sensor Rate = 165 bpm



Paced AV = 180 ms

Sensed AV = 150 ms



Rate Adaptive AV = On

Start Rate = 90 bpm

Stop Rate = 175 bpm

Min PAV = 80 ms

Min SAV = 60 ms



ADL Rate = 125 bpm

Optimization = Off

Activity Threshold = Low

Activity Acceleration = 15 sec

Activity Deceleration = Exercise

ADL Setpoint = 26

UR Setpoint = 57



PVARP = Auto

Min PVARP = 250 ms

PVAB Interval = = 150 ms

PVAB Method = Partial+

A. Blank Post AP =  200 ms

A. Blank Post AS =  100 ms

V. Blank Post VP = 200 ms

V. Blank Post VS = 120 ms



by PacedNRunning - 2022-03-05 01:25:18

Your settings are very similar to mine and I'm 100% paced in the RV 

PAV 80-180ms

SAV 70-160.

50-185 bpm

are you having issues with exercise? I had RR on in the beginning and I never needed it with exercises because my heart could regulate exercise.  It's only there as standby. So if your own heart is doing the work, it won't pace. When I first got my PM I had issues with settings when I intermittently paced. Now that I'm a 100% paced, it's way better. Intermittent pacing was not ideal. 


by SNORTINGDONKEY - 2022-03-06 17:06:03

Hello....looks like we have very similar problems. RR is OFF on mine too. I am also 100% paced. My SA node is working fine and supposedly is driving the AV node "naturally".

Yes, I am having issues while running...what happens is that after running for a few minutes, I feel as if something is not in sync and feel as if I am short of breath. It feels as if the HR is "artificially" increasing when I don't feel as if my body needs it...meaning, let's saying I am running at a certain pace at 125 bpm, even if I were to keep the exertion constant, the rate continues to increase regardless and that's when I get that out of sync/short of breath feeling. Earlier my Upper Rate was 175 and we brought it down to 165 last week. The change did make a difference for the better, in that I feel as if it is a little more in sync.

Given that RR is OFF, the values of ACTIVITY THRESHOLD and UR SETPOINT should NOT matter, correct?


I saw your other response about PVARP...how did the EP-tech optimize it for you? Was it just trial and error or was there some fancy lab/jig? Just out of curiosity, what are the values for ADL RATE, ADL SETPOINT, ACTIVITY THRESHOLD and UR SETPOINT for you?



by PacedNRunning - 2022-03-07 04:26:09

I had the same in the beginning where my HR would speed up. Felt out of breath and like I was 100 years old.  They thought I was having PAC's while running but when I looked at the machine with them I pointed out that they couldn't be PAC's because it was too regular.  They then noticed that the device was double counting and fixed it.  I have Boston Scientific so we can capture an ekg (with a magnet) of what I was feeling while running. They would be able to see what I was feeling and make adjustments. I also did a treadmill session that helped some but most of my adjustment were captured with a magnet they gave me.  The bad thing about the magnet it's a one shot deal.  You can only capture 2 mins at a time and I would have to go back in and have it reset to capture another event.  I don't have any activity sensors on. They are all off for me.  It interfered too much with me to keep it on.  

I'm not sure if this is rare of not. But one last adjustment that made a world of difference is my heart with exercise would just drop P waves.  They turned on rate smoothing to help with the fluctuation with dropped P waves.  They never really said if it was the device not seeing my P waves while exercising or sinus exit block.  They only said my P waves shrink with exercise. I did find a really old research article about exercise and rate smoothing for those with CHB and they mention rate smoothing. I took this information to my EP and we turned it on to see if it worked.  It worked great! That too needed to be adjusted. It can be 3-24%. We started at 18% then 15% then 9% and finally 6% was the smoothest.  I just felt like someone was choking me while running. My breathing would become really labored when I would drop beats from the top chamber. If you google ratesmoothing, pacemaker, exercise you may find the article. It's from the 1980's.  

Can they turn off all RR?  I"m not sure how they adjusted my PVARP. I believe my PVARP with exercise is 150ms to 280ms.  I found adjusting these things for exercise takes a lot of patience.  I use to write down how I felt when I was exercising. I found if I keep my HR under 160, I felt better than if I stayed over 160bpm.  I would write things like,I feel great from 120-140bpm after 140bpm I start having breathing problems. Etc.  I found taking those notes help report back to my doctor to help make adjustments. I also suggesting sticking to one sport while adjusting it because different sports can make things feel different and it's too many moving parts.  So I picked running and adjusted it for running.  Works well for other sport because my other sports, golf, hiking, biking my heart rate stays under 150bpm and that's were it always felt the best.  Let me know if you have any other questions.  :) 


by SNORTINGDONKEY - 2022-03-07 12:23:27

Thank you so much for taking the time to write all this up!

- Good idea about the EKG...I am not sure the magnet is an option with my PM...but I will ask the doc. But I wonder if I can simply use my Apple Watch's EKG to do the same...no harm in trying I guess...I am going to try it during my next run.

- On my PM, they have turned off the RR (see RATE RESPONSE settings above.) I am assuming/hoping that has turned off all activity sensors...but I am reading the manual again just now and I am noticing one word there that can be construed in different ways. I will check with the doc just to make doubly sure that none of those RATE RESPONSE settings above are active.

- Yes, I have been pretty much documenting everything - how I feel, etc.

- I am only adjusting it for running.


You’re Welcome

by PacedNRunning - 2022-03-07 19:36:32

hang in there! It can be frustrating at times but keep at it! I had to keep asking myself "is this tolerable?" Yes or no?  No, meant another adjustment but it would take me a good week or 2 to really decide if it was tolerable or not.  Best of luck! You will get there. 


by PacedNRunning - 2022-05-11 01:19:54

My min PVARP is 150ms. That could be your issue. The PVARP controls 2:1 block point. Perhaps it's too long. The P waves are getting buried with a long PVARP,  May need to shorter for exercise because it will put in you wencekbach.

just a thought. 

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