Optimised AV Delay

Hi, I'm almost six weeks post implantation, had my post surgery follow-up at five weeks and I'm back for a pacing check in three months. I'm currently v-pacing a high percentage of the time and I'd like to know know if I should be requesting any specific tests at my pacing check.

In my five week follow up I mentioned my programmed av delay (250) might be one reason for excessive pacing, so my cardiologist (with guidance from the Medtronic rep) extended it out to 350 paced and 350 sensed. This didn't have any impact on reducing the amount of pacing but did make me feel terrible (as I did pre PM). I called back into the clinic and my cardiologist everted the av delay to 250. I now feel great again but I am still concerned about the amount of v-pacing which is most of the time unless I'm exercising.

Pre-PM I have a persistent second degree block, present all of the time unless exercising. During exercise and for a couple of hours after I would have a first degree block with a PR interval between 250 and 320. My Brady was at 25-35bpm.

My PM is a Medtronic Azure XT DR MRI SureScan  in DDD mode, low at 40 and paces up to 60 and the AV delay is at 250.I understand the long term issues with v-pacing so obviously want to have things optimised as soon as I can.

3 Comments

"My Brady was at 25-35bpm"

by USMC-Pacer - 2024-03-15 10:25:53

I'm not familiar with Brady.. my HB was opposite of yours as it would act up when my rate went above 125 which at the time they called it exercise induced. If you have Brady, I would think it would have to constantly pace your ventricles above your 25-35bpm? If I'm not mistaken, I think the AV delay is the device timing / sensing to give your sinus the opportunity to send the impulse to your ventricles before it paces for you. Sorry if that's not helpful.. others will be along to help..

How do you feel, that is what is important

by Gemita - 2024-03-15 11:27:49

How we feel with our pacemaker is more important than worrying about those numbers.  If we feel well, then chances are that we are pacing the correct amount of time.  You have already told us that changing the AV delay resulted in you feeling terrible and that it didn’t reduce the time you were pacing in the RV so this tells me that you need a high degree of RV support.

Ryan, it sounds to me as though, without symptoms and feeling great, you have things optimised already, so why change anything??  

When you next see your cardiologist/EP you could always discuss your concerns for the future with a heavy percentage of RV pacing and ask what he/she would do if you developed heart failure symptoms from any dyssynchrony between your ventricles.  My EP told me (and I am also in the UK) that they would upgrade me to a CRT should I ever show signs of developing heart failure.  (They clearly wouldn't do it before).  I see you have both bradycardia and heart block.  I have signs of both too but I am almost 100% paced in my right atrium in AAI pacing mode, with minimal RV pacing fortunately and this suits me very well, but so do your settings and current mode and that is what really counts.

Edit:  In case of interest, my Paced AV interval is 180 ms and Sensed AV interval is 150 ms

Thanks!

by Ryan_CX - 2024-03-15 13:23:48

This is a great reply Gemita, thank you, you are totally right. Having had totally inappropriate settings corrected I know what the difference between normal and terrible is - and these settings currently work great, I feel like I am in my 30's again (I'm 45). That's why I had the PM and so it is doing its job perfectly.

I am going to stop overthinking things (spend less time looking at my ecg's) and enjoy the positive changes that the PM has given me. I'm going back to my trusty analogue watch before this Apple Watch turns me into a hypochondriac.

For completeness, I'll update this when I have my next appointment but otherwise I'm going to quit stressing about it and let my cardiologist do his job. 

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