Update on Pacemaker Mediated Tachycardia

PVR?

by Gemita - 2024-04-24 14:23:43

Hello Ukegirl,

Thank you for the update.  Can I just confirm what the PVR is.  Would this by chance be the PVC Response and the related PVARP setting that has been adjusted from 225 to 325 milliseconds after you had a positive retrograde test at 286 milliseconds.  Hopefully that increase (in PVARP?) will prevent pacemaker mediated tachycardia.  Please keep us informed.  This is the first time, to my knowledge, any member has given us a settings change (in milliseconds) for pacemaker mediated tachycardia.  I hope it is the magic adjustment that works perfectly for you.

Gemita

by Penguin - 2024-04-24 16:55:56

I 'think' (as you infer) that Ukegirl is referring to PVARP.  Often PVARP setting is extended. Not sure that there is a standard adjustment used (although there may be). I'm assuming that there's a bit of trial and error involved.  Modern pacemakers detect PMT automatically via PMT detection algorithms and extend PVARP outwards I believe.

I don't know about other PM manufacturers but a PMT detection rate may be programmed for the algorithm to work.  If the PMT occurs below this the PMT detection algorithm may not work. 

I'd be surprised if Ukegirl's newer PM doesn't have an automatic PMT detection setting?  It's listed on the interrogation if it is set up. 

postventricular atrial refractory period (PVARP)

by Gemita - 2024-04-24 18:46:12

Thank you Penguin. Yes I agree we are likely talking about the setting PVARP, also known as post ventricular refractory period.  I note from Cardiocases, on Biotronik management of tachycardia (since I see Ukegirl has a Biotronik pacemaker) the following:

- the PVARP can be programmed on Auto or on a fixed value

- after a PVC, the PVARP is automatically extended to PVARP + 150 ms, up to a maximum of 600 ms

- if the PVARP feature is set to AUTO, the value of PVARP is set to 225 ms and PVARP after PVC is set to 375 ms; once a pacemaker mediated tachycardia is detected, the algorithm automatically extends the PVARP and PVARP after PVC by 50 ms, up to the maximum value of 600 ms

My Medtronic “PVC Response” extends the PVARP following a PVC to avoid tracking a retrograde P-wave and to prevent retrograde conduction from inhibiting atrial pacing.  When my device senses a PVC, the device forces the PVARP to be at least 400 ms.  Because retrograde conduction normally occurs within 400 ms of a PVC, the retrograde P-wave will be within the PVARP and will not be tracked and will not inhibit atrial pacing.   This prevents PMT and preserves AV synchrony.

As you say, it will probably be trial and error to get the settings fine tuned for Ukegirl, but I hope she will remain pacemaker mediated tachycardia free with her current initial settings changes

PVARP and other settings - advice please

by Xtrabeat - 2024-04-27 06:10:36

I am very intersted in the comments above. My pacemker has been adjusted three times since implanted last December. Initially switched rom DDD to VVI because of what was thought to PMT due to retrograde conduction. I was OK for a while but developed symptoms on exercise (light headeedness and weakness) and it seems I get AV dissociation at higher heart rates(above 100) and that for some reason the heart rate does not respond to exercise like it used to. Even on a treadmill I could not get a rate above about 110. So DDD with rate response was instituted and I developed pain, breathlessness and lightheadedness with a rate of about 130+ which was felt to be PMT  - so rate response turned off and what was called atrial blanking (I assume PVARP) turned to maximum (don't know the value) since which time things are improved but I am still limited on moderate exercise. This is a major worry as I am a keen hill walker and I now have to stop and rest on steepish inclines and really would not contemplate anything remote or challenging - quite a contrast from last year with all-day walks in hilly country. Do you think there are any further tweaks that might help or is this the way things are going to be? I am concerend that getting enough time with the PM physiologists will be a difficulty in the future - I am beginning to feel that I have exhausted their patience. 

Xtrabeat

by Penguin - 2024-04-27 07:28:03

It may be wise to start a new thread to discuss this Xtrabeat - unless Ukegirl is OK with the thread changing to discuss your own (probably very relevant) issues? 

As a short response, you should be able to get your Pacemaker adjusted for exercise. It may be helpful to request an exercise / treadmill test so that the technicians can see what is happening and how the pacemaker is behaving whilst you exercise. 

Correction from PVR to PVRP

by UkeGirl - 2024-05-02 18:23:58

Hello, again,

The adjustment in my settings was made in the PVRP to reduce the PMT.  The adjustment was made a little over a week ago and I've not received any information about a decrease in PMT but my heart rate isn't shooting up as high when I initiate activity so in that regard I feel better.

I still have some palpitations along with periods of lightheadedness after PVCs that last from a few minutes to hours. The NP at the EP Clinic wants me to track my blood pressure and return if I have ongoing episodes of rapid heart rate.  I was told that multiple tweaks in settings especially during the first year of pacing is common.  That was reassuring not knowing what "normal" may be.

Thank you again for your comments!