AV VV Delay?

CRT (cardiac resynchronization therapy) optimization

by Gemita - 2024-10-02 18:43:58

Hello USMC-Pacer,

I am so sorry you are having to struggle with optimization all over again, but you know this time that it is even more important to persevere because of your CRT.  You want the best synchrony you can get for good results.  This might be slightly more difficult to achieve but it is clearly so important that you get those ventricles perfectly balanced as well as your AV synchrony.  

Is there any suggestion that you are a non responder to CRT pacing, or is it just the synchronization between the chambers that need more attention?   Has your EF improved?  

Your comment:  Last time at the clinic we decided to leave well enough alone and not to get into the CRT AV VV optimizing, as in their words, it can be time consuming made me think that would not be good enough for me.   Why have a CRT if we don’t get the very best out of it?

We know that implantation of a biventricular device is challenging, but the programming afterwards is just as important if not more so, so I would push respectfully for optimization, however time consuming!  I have complete confidence that you will succeed as you did before.  

I expect they are going to fine-tune your device by echocardiography for the best AV and VV timing; this is called CRT optimization?  

What sort of a fight do you get into to produce that 2:1 block!  Sounds interesting?  Could the 2:1 block be caused by a tachy arrhythmia triggering mode switch too early?  I know mode switch can restrict the upper tracking rate and trigger 2:1 AV block during exercise.  You could ask whether you need Mode Switch turned on or whether you could manage with it off, especially if you don't have tachy arrhythmias.  Or alternatively ask if it is perhaps possible to raise the rate at which it switches to a non tracking mode?

Well I will say goodnight and wish you well as always.  Take your time with this and get it right.  Good luck

Gemita

by USMC-Pacer - 2024-10-02 20:45:01

"What sort of a fight do you get into to produce that 2:1 block!  Sounds interesting?" 

Haha.. I'm a retired Correction Officer. I was asked a few times to do part time or as needed shifts.. NO THANKS! But, it got me thinking that if I did, or if something sudden like a fight with an inmate, or anyone happened, I'd be junk quickly when my HR goes to 70bpm when I need it the most :)

Aside from that, she got back to me today. When they made changes to my AV Delay years ago, I still had some of my own conduction left. Now, I do not, so she doesn't think optimization is the issue at this time. They keep the AV and VV delays as short as possible. She thinks she found the issue:

What she found due to my whining, is that I have a setting that tracks arrythmia, A-fib, SVT, etc..that will cut off at 120-130bpm. So, if my HR jumps up quickly, which is when this happens, it will make the device think I'm having one of the above conditions and put me into?.............................you guessed it, a 2:1 block, or as she put it, the device blanks signals from the atria causing skipped beats.

Tomorrow morning I'm going in to have that adjusted to match my upper limit of 150. I'm going to try to talk her into raising both to 160 :) Wish me luck!

Upper rate behavior vs Atrial tachy response

by Rch - 2024-10-03 02:45:14

Hi

I have a BSC Accolade dual chamber implanted 2 years ago for exercise induced 2nd degree heart block. My TARP adjusted MTR (Max Track Rate) is 130 and the ATR trigger rate is 170. I'm not sure why the Atrial tachy rate ( AT, SVT etc) is set far below the MTR for you? It would mode switch at the ATR trigger rate, and your HR would never rise beyond the trigger rate. Does the PM record the mode switch event ? What I am guessing is that your HR does shoot up all the way up to 150 with vigorous bursts of exercise and you do go into the upper rate behavior with 2:1 or Wenckeback. It all depends on the accuracy of the device you use to check your HR. If you use Kardia, you can precisely check your heart rates and the wave patterns, and from that you can get some rough idea as to whether you are in a 2:1, wenckebach or some other rhythm. Hope you will get some answers soon!

Sounds positive

by Gemita - 2024-10-03 04:03:00

Of course I wish you luck, USMC-Pacer, although I feel you are already a lucky man to have a caring female EP who goes away almost immediately to study your downloads and pinpoints perhaps the main cause of your symptoms?

“the device blanks signals from the atria (?inhibits pacing) causing the skipped  beats”.   Couldn’t be clearer and this suddenly slashes your heart rate causing symptoms.  I hope the adjustments work well for you without the need for further changes to your AV and VV delays or other settings.

You sound fit enough to get both those limits raised to 160 bpm although I would certainly stay away from those inmates for the time being until your settings are optimised and fully tested.   My Mode Switch for AF, SVT and other atrial tachy arrhythmias was initially set at 171 bpm.

Rch & Gemita

by USMC-Pacer - 2024-10-03 08:19:06

Thank you for your comments. My EP/NP is awesome and very responsive to my needs. I always try to seek her out as she knows the issues I have had. It's not always possible, but most of the folks in that clinic are great! She says that "younger" :) physically fit patients are a learning curve with these devices. Over the years I've had my share of issues, always during exertion with both of my devices. She has always jumped right in and fixed the problem. I have no doubt this time will be the same. 

Rch, I have no idea why my arrhythmia setting was lower than my MTR, but here we are. If I do gradual exertion like walking, cycling, weightlifting that typically raises HR slowly, no problem getting to my MTR and beyond (which I avoid....most of the time) :) But, throw in a rapid exertion like a sprint, running up stairs, one time it was shovelling, and most recently I was on a dirt bike and had to fight it up a slope of large wet rocks (not fun having to stop in the middle of that, gasping!) That low setting does sound a bit like an oversight. This has been happening for a while and I dealt with it as it isn't that often that I exert myself that way. I should have addressed it sooner. 

"Does the PM record the mode switch event ?"

I asked her if I could give her an exact time of episode to see if it would show up on my device EGM, but she said it is not set up to record that? It also never reports my numerous times exeding my MTR and getting thrown into the dreaded 2:1 - interesting, I always expect to get the lecture of a "too high" heart rate but never do :)

Rch and USMC-Pacer

by Gemita - 2024-10-03 19:10:26

My  pacemaker “counts” all the Mode Switch events that have occurred, but only when they meet the criteria set up by my EP for their reporting.  As we know, that is, the tachy arrhythmia has to be above a set rate and for a certain duration before it is counted and shown in any arrhythmia episode list.  Only a few significant events will be recorded on the internal EGMs since there is only room for a limited number of these to be stored.  Less significant events which do not meet the criteria for their recording/reporting will be ignored, so Mode Switch alone is not a true reflection of total arrhythmia burden.  This is why we may still need external holter or other monitoring in addition to our devices, to confirm slower, less significant rhythm disturbances.

So I agree with your EP, USMC-Pacer, that your device won’t be set up to “store” too many EGMs, although your Mode Switches that meet criteria will be counted to give your doctors an idea of any "significant" events and of your arrhythmia burden.  For example over the last few years my Mode Switches have decreased from 2,000 (AF/Flutter) over 3 months, to around 200-300 over three months today.  These are for mostly brief, in and out episodes, so cause no real harm.

As a matter of fact I did ask the very same question you asked USMC-Pacer.  On one occasion, they did have one of my significant arrhythmia episodes stored on an internal EGM and were able to discuss this at length.  It transpired that my atrial ectopic beats were clearly shown on EGM to have triggered the episode of atrial fibrillation.  My technician turned up the sensitivity of my atrial lead, to ensure that more episodes like these could be caught and analysed.  So keep your records USMC-Pacer.  They may prove valuable.

Still learning

by piglet22 - 2024-10-04 07:32:24

You guys are streets ahead of me, I always haveto look these things up.

Of course, the web is full of information, but this looked interesting.

https://litfl.com/av-block-2nd-degree-mobitz-i-wenckebach-phenomenon/

0 episodes were recorded...

by USMC-Pacer - 2024-10-04 10:45:57

So, like the above says, there were no episodes logged from the EGM. She matched my MTR and ATR, but wouldn't raise the MTR without the doctor's approval, maybe later. I'm fine where it is for the most part and rarely hit it. I think it was the lower ATR that was causing the issue and I plan to put that to the test soon :) She also made some changes to the PVARP, but I forget what she did..

Changes to PVARP

by Rch - 2024-10-04 17:48:17

It would be interesting to know what your EP did with the PVARP as it would also affect the AV delay given your unchanged MTR. If the newer settings really helps you, it would certainly be more educational or helpful information to the forum members to discuss their own individual situations with their providers. I always request a copy of the visit through medical records! Hope the newer settings will work for you! 

She will post comments on their portal..

by USMC-Pacer - 2024-10-04 19:50:37

They always post after visit notes on their portal. Sometimes it takes a few days. She squeezed me in as she was doing "inpatient" that day and was leaving after she saw me.. so, I'm guessing there will be a delay... Or, maybe it was a freebee :) If I don't see it, I'll email her and ask. You're right that all this info can be helpful. I'll report back!

Rch

by USMC-Pacer - 2024-10-07 14:21:56

@Rch or anyone interested in the changes the NP made in reference to the above:

PROGRAMMING CHANGES: Max sensor rate increased to 150bpm. PVARP shortened to 150ms. AT/AF atrial interval detection increased from 171bpm to 188bpm. I made no changes ot his max tracking rate or any of his VT/VF zones.

So she increased my ATR to 150bpm from 130bpm. She decreased my PVARP from 260ms to 150ms. It seems to be working, but I'll challenge it more going forward. Hopefully this is hellpful to others here :)

That is useful info USMC-Pacer

by Gemita - 2024-10-07 15:04:42

My PVARP is 160 ms, so much the same.  My mode switch detection rate was 171 bpm but seems to be 160 bpm today, so clearly I will be troubled by more in the way of switching.  I really hope your changes work and you will notice some real improvements

So far...

by USMC-Pacer - 2024-10-07 18:59:04

Worked out nice and hard today and had a tougher time getting to the 150 upper rate. I got there and beyond and never dropped into 2:1 :) My rate also recovered (HR recovery) much quicker too. Not sure if it's related, but felt great!

I haven't tested the fast increase in HR yet, but I will!