Total AV block- Looking at Medtronic Micra AV,


I'm a 36yr old father of 3, and I've known about my total AV block (as diagnosed at least) since I was 18.  My resting hr has steadily been dropping from the high 40's in my late teens to the high 30's now.  My maximal hr is about 130, and I can maintain steady exercise in a relatively normal fashion. 

I've put off a pm due to the length of time I am likely to need one.  I'm still asymptomatic (at least for any dramatic symptoms like passing out, I may be suffering symptoms I am unaware of).  Increasingly, I am concerned about what happens WHEN I become symptomatic and I pass out, since I could be behind then wheel, etc.  As a result, I'm getting the pm this summer. 

My doc has suggested the recently approved Medtronic AV for me.

Does anybody have any input/experience that may be worth considering?  Thank you very much for anything you can add.



Doesn't seem a wise choice

by crustyg - 2020-06-30 06:57:43

Odd.  You say that you've put off getting a PM due to the length of time you're likely to need one - and then you say that you're considering a PM model that was approved early this year!  Let me consider that: it's something that you'll have for 30-40 years, there is probably less than 2years of patient experience with this device (in any setting), it has a tiny battery, you have no idea what they will do when the battery runs down, and you need your third or fourth device with the others still embedded in your RV - oh, and it's going to be pacing the apex of your RV which is probably the worst possible place to pace the heart (other than not pacing it at all). [Edited - this *may* not matter so much for CCHB folk, but it matters a *lot* to those with damaged/diseased heart muscle]

Pardon me for being blunt, but I don't think the advice that you've been given is appropriate for you and makes me wonder about the motivations involved.

Read up on some of the posts here from folk with congenital CHB before you make up your mind.  At the moment, you have a healthy Sino-atrial node which generates the electrical pacing signals that your ventricles need as you move and exercise/play with the kids etc. but which can't reach the ventricles due to CCHB.  So what you need is a device that listens to your SA node (RA/RA-appendage lead) and then transfers/duplicates that signal to the bundle of His, which restores normal physiological pacing to R+L ventricles, maintains AV node synchrony and which will, with an extended life (==bigger battery) last you 12-15years before the PM box needs replacing (simple skin incision under local, 45min from start to finish to connect up a new box when you need it).  Yes, leads don't last for ever, but there are folk here with leads 20years in and working fine.  There are specialist centres that are really good at replacing worn-out/failed pacing leads safely - all the mistakes and learning has already been done - on other patients!  You'll be a guinea pig when your first/second Micra +/- AV runs out.



by dwelch - 2020-06-30 10:09:37

I have cchb, am shocked they waited this long if yours was from birth and they found it at 18 they should have put it in immediately.  Pre pacemakers CCHB takes you out in your teens, the odds of making 30s is quite low.  Granted they waited several years on mine, but I was getting checkups and lying to the doctor about my activities (was a teenager).  It should have killed me, I got lucky.  (the wait was driven a lot by heart size and muscle wall thickness once it got to a certain point that was it, pacemaker time).

As far as the device, brand and model, that is the doctors choice, you tell the doc and your activities, understand that with a heart block your heart rate which is measured from the lower chambers is somewhat wrong right now as your heart doesnt work right, the lower chamber is working harder.  Yet you may still want to ask for a device with a higher limit or be set at a higher limit.

The best thing you can do for you and your family is get this device, a lifetime of devices is not a problem. I am at 33 years, someone on this site is at 40 years. Im on device number five.  I have a 33 year old lead a 26 year old lead and a few year old lead (am on a biventrical now) and one broken 33 year old lead that is still in there, broken between number one and number two.  Back then you didnt take leads out or it was a major deal, there are docs good at it now.  

Heart block is trivial to see on an EKG at this point they should have shown it to you many times, if not just google it you can see the beats dont line up, the ventricles wander about on their own.   The doc should have shown you this on one of your regular visits, and shown or at least talked about why such a long delay in acting on this problem when there is a trivial solution.  No special test required a few seconds on an EKG is all you need to see complete heart block.

You dont want to wait to be dont want to wait...

Find a doc you trust and trust the doc you find.  Not sure I would trust this doc but im not there, im not in the room I didnt have the conversations, wasnt shown the information, etc.

I got my first device at 19, they found the problem pre teens and watched it.  33 years in so you can do the math.  Still on the left side and so far so good, still have the other side to use for the other half of my life and/or they can put it in the abdomen, etc.  In hind site I should have been more honest with my activities and gotten one sooner, granted (and we have some here) when you start as a kid you are still growing and im tall so I had the 9-10 inch growth year in high school that would have been a mess, granted they dont always use the shoulder until you are an adult is what I understand from this site.

The major brands are all fine, there is no better, the leads are interchangable I have medtronic, guidant and boston sci leads, have had medtronic, st jude and boston scientific pacers.  As answered above because our lower chambers need the device nearly every single beat to get that 10 year plus or minus ideal battery life we get bigger batteries than some other folks.  Compared to my first one these things are tiny today.  They will show usage at 100% if you have complete av block, or depending on how the device measures that statistic basically high 90%s.  Can debate words like dependent or not as you know now you can live without it at least for some duration, your heart wont stop, as part of your regular checkups they will stop the device or at least stop the lower end and see the underlying natural rythm and if they show you that ekg, that few seconds is more than enough to still see the block.  Last visit the tech was training another and let it go a bit longer and then showed the student what block looks like. 

Pacemakers are easy to live with, easier than glasses, etc.  Its like a belly button or big toe, you know you have them but dont think about it unless you stub one.   There is a transition period the first so many months or year.  In my case I could feel and hear every heart beat up to that point it was just normal.  When the pacer fixed my heart that was all gone an eerie emptiness.  Was regularly taking my pulse.   Back then the devices were less automatic and it took a number of visits to dial it in.  Since then though not much adjustment if any has been needed.  My current doc they tweak one parameter as needed perhaps to tease out a small amount of battery life.   Devices get better every time I get one, so you wouldnt want an 80 year device even if they had one.  10 years per is the right compromise.  

I was in the 40s when I got mine, spent the night before and was told I was in the 30s when sleeping.  my EF (ejection fraction) was on a slow and steady decline all this time when it got into the 30s it was time for a biventrical (not uncommon, aint no thing, just another lead you dont feel nor care about) and instead of just stopping the decline it increased the EF.  They will do occasional echocardiograms to look for things like this.  When you get 15 years in give or take they may/should start checking every year.

Good luck, welcome to the club.


ditto crusty

by Tracey_E - 2020-06-30 10:28:45

I'm with Crusty, I would not want something so new and untested in the long term when I'm going to be paced for a lifetime. When the Micras first came out (not that long ago!) being dependent was a reason to be denied one, and with av block we almost always eventually end up pacing 100% of the time, or nearly 100%. Also, in theory we only need one lead with av block but in reality sometimes we need that other lead. I pace 100% ventricle, 4% atria.  Usually my sinus rate is fine but sometimes when I work out, it drops quickly, other times it doesn't go up quickly enough. Those are the times the other lead kicks in. Maybe get another opinion first? Someone in a different network because another doc in the same network will read the chart and tell you the same thing. I'm certainly no expert, just someone who's been living with a pacer for a long time. I love the idea of not having leads because that's the weak point in the system, so I've kept an eye on the Micra. I just don't think it's there yet. 

Whatever you choose, I agree it's smart to get it before you pass out. When you are passing out is too late. I think you'll be surprised how good you feel after. I was not expecting the surge in energy I got with my first pacer. If we've never known any different, we have nothing to compare it to, and I think as we age and our rate drops, things change so gradually that we compensate for it and don't even realize it's happening. I could tell the difference the minute I woke up in recovery, like I'd been mainlining coffee. I got in trouble that night for pacing the halls when I was supposed to be in bed, but I had too much energy to sit still. Not everyone feels that drastically different but your numbers are similar to mine. 

For me, it was night and day. My rate was 44 all my life, did not go up or down, then it dropped to the 30's. The day I got the pacer, my rate tanked to 22 and I ended up in emergency surgery. So I speak from first hand experience when I say it's good to get it done sooner than later. In hindsight, I should have had it several years before I got it. I could have been feeling good all that time but I had doctors who didn't want to pace someone so young. I was 27 when I got the first, btw. I'm 53 and on my 5th now. I still have one original working lead, the other was replaced when I got pacer #4 about 10 years ago. I'm healthy and active, the pacer doesn't keep me from doing anything I want to do, and no one looks at me and thinks heart patient. Most of the time I forget it's there. 

Micra AV

by AgentX86 - 2020-06-30 13:47:10

At your age, I'd be leary of a Micra but for different reasons than stated (at least stressed) here. You're going to need several PMs during your life. As it stands now, when a replacement PM is needed,, the intention is to leave the current Micra in place and drop another in beside it. There suposed to be room for three, or so, in the RV. The things do have a port which can be used to snatch it and pull it out the way it went in. This hasn't been done, yet, at least outside of the approval process. I don't think I'd want to go down that path, knowing that I  have to go down that path, perhaps five or six times.

The Micra AV is, in effect, a two lead device for the purposes of heart block because it does sense the atrial contraction and maintains AV synchrony. It'll also track your SI node so chronotropical competency is maintained. However, there is no LV lead possible,  at least yet, so LV/RV synchrony could be a problem down the line.

You positively need a pacemaker but I think you should do your research and challenge your EP on his suggestion of the Micra AV at this time.


by thesteven619 - 2020-06-30 14:10:27

Thanks all for the good points.



Hi Steven

by jamfer - 2020-07-01 16:16:20

I'd encourage you to get a PM device for all the reasons that you listed but especially for your three kiddos.  I didn't get a choice of which device was implanted.  Sounds like you have an opportunity to make an informed decision regarding the device.  Don't shy away from getting a second opinion as well.

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