Pacing Trends

Hi, my condition is an AV Block 3rd degree, and had a Biotronik Enitra 6DR fitted 3.5 years ago, following which I had no further symptoms at all.  About 4 weeks ago I noticed during light exercise a tightness in my chest, along with light headedness.  This continued for some days, and after a visit to my doctor he suggested I have my pacemaker checked.

They checked and said the pacemaker was performing normally, but did notice that about 4-5 weeks previously the "Pacing Trends" graph had jumped suddenly from an average of 12% over the previous 7 months to 100% (I have a photo of the graph). This seems to coincide with when my new symptoms showed up.  Just wondered if this is something I should be concerned about? 



Pacing changes

by AgentX86 - 2021-05-23 13:32:18

Did you have any adjustments made to your pacemaker at the time this happened? It's easy to have this sort of change if they made any changes, like the minimum rate.

BTW,  which pacing percentage changed? RA or RV?

If there is nothing to explain it, I'd be looking for a reason.

Trying to work this out

by crustyg - 2021-05-23 14:13:35

OK, so you started with 3rd-degree HB (==Complete Heart Block).  Therefore your RightVentricle lead would be pacing all of the time (or very nearly), detecting atrial activations and transferring them to the RV bypassing the CHB.

12% atrial pacing I can easily believe, suggesting that your SinoAtrial-node (the natural pacemaker that drives heart rate (HR)) wasn't in great shape. Therefore my conclusion is that your SA-node has failed completely =>100% pacing.

And you feel terrible during light exercise because (if my hypothesis is correct) your HR isn't increasing as it should (and used to when your SA-node was driving your HR when you needed an increased cardiac output).

If I'm right, you need Rate Response to be enabled (should have been off with CHB and a working SA-node) and tuned for you.

OK, against my hypothesis: your (heart) ElectroPhysiology-team should have been a little more proactive than just 'noting' that your pacing percentage has increased from 12%=>100%.

Something doesn't add up here.  Time to get your PaceMaker reports...

Pacing Trends

by simonva3 - 2021-05-24 12:21:46

Afraid I know nothing about pacemakers and am not familiar with the abbreviations above.  All I can say is that, according to the graph legend (A and V) there is only the 'V' line showing, so is this RV?  The technician made no changes to the pacemaker settings, and only in passing mentioned the unusual graph.  He said the pacemaker was working correctly!

Looks like I'll have to press my GP to get some answers. 

RV or V

by AgentX86 - 2021-05-24 13:10:36

Yes, the 'V' means the same thing as "RV".  A 2-lead pacemaker doesn't have a left ("LV") ventricle lead.  12% V doesn't sound like third-degree heart block at all, maybe first or second.  I'd be asking some questions but your GP isn't the one to be answering these questions.  You really need to go back to your EP to get this cleared up.

"Looks like I'll have to press my GP to get some answers"

by ar_vin - 2021-05-24 13:42:02

This is NOT a GP level issue - you're unlikely to get any help from anyone other than your EP (cardiac electrophysiologist) and his/her device tech(s).

As has been suggested above, you need to reach out to your EP.

"Afraid I know nothing about pacemakers and am not familiar with the abbreviations above"

It is CRITICAL that you get familiar with your PM and it's settings - start with your PM vendor's website and ask questions here once you've done some reading.


Not going to disagree with any of the comments above

by quikjraw - 2021-05-26 12:40:55

I would only add that when you get chance try and share the photo of your download on the members gallery.

Unless of course you are now sorted?

All the best


Pacing Trends

by simonva3 - 2021-05-27 10:24:35

I've now spoken to my GP ( in UK we don't normally have direct access to consultants or specialists) and have been assured that I have been referred to a cardiologist at the nearby hospital, although having just spoken to the department there's no certainty I'll be seen in days or even weeks!  Our medical service appears to be overwhelmed due to recent lockdown relaxations.

Anyway, I've posted the photo I took of the pacemaker graph.  The bottom time axis is spread over 8 months, with the sharp rise in pacing occurring about 5 weeks ago, seeming to coincide with the start of my symptoms.  I'm just going to have to wait now, but in the meantime intend to continue a normal life (but cut out the marathons, rock climbing and sky diving!!)

I've looked at the graph you posted

by quikjraw - 2021-06-01 06:22:57

Hi Simon,

The graph you show does show a clear change in pacing. I am assuming that this graph represents the amount of Ventricular pacing over a period of 8 months.

As AgentX86 said your pacing figures suggested your block did not seem to be third degree in those preceding months. If you had constant third degree block you would not have been pacing in the ventricle 12% but 100% of the time.

It is interesting you feel your symptoms coincided with the change in pacing. This could be coincidence or it could be very much linked.

I would strongly echo all the points above that your symptoms and pacing graph signify the need to see an EP or cardiologist which you are already trying to arrange.

I am also in the UK and I agree there has been a real drop off in non-covid NHS healthcare but I think what you are experiencing warrants a relatively quick appointment with the EP or cardiologist. If you are not getting anywhere find out the numbers of some of the cardiologists' secretaries and see where your appointment is in the process. Sometimes they do not appreciate how quickly you want to be seen. 

When you do have your appointment I would ask whether they can help you understand the following

1) What is the current status of your heart block

2) If it has now gone to full heart block (third degree) are the pacing settings suitable during exercise.

I found out a few weeks back that my heart block was such that during exercise when my heart rate reached the tracking rate limit of the pacemaker (the limit at which they had set the pacemaker to follow a atrium based beat to pace the ventricles) I was effectively in 2:1 block (so every other beat from the atrium was being followed by the ventricles). 

This meant that my effective heart beat had maxxed out at 150bpm. (before my implant I would often reach 180 to190bpm during running) I could see it on the screen during the treadmill test. Your third degree heart block could mean that during exercise you are also being limited.

the good news is that they can make adjustments to ensure your pacemaker is doing more to support your during exercise.

I hope you can get back to exercise soon, I know how important it is.

All the best John

doesnt sound right

by dwelch - 2021-06-02 00:45:37

if you have 3rd degree it should be near 100% all the time on the V lead.  The atrial lead if you saw an increase possible that your rate was too high for some reason and the pacer was taking over, that or too low and the pacer was taking over.

Need the EP to try to explain why you have 3rd degree (complete) block but do not have consistent 100% usage on the ventrical leads.  should have also explained to you various reasons why you could have had that event.

I have complete heart block, from birth, 34 years with pacers.  there are days that you just feel off independent of pacer, too tired, too exhausted, etc.   But as in your case you now know that sometimes the log will match what you saw.  Just call the doc if concerned, they can do an interrogation see if anything is off with the device or if you just had an event.

I also had a sudden increase in pacing

by Elisabet - 2021-07-17 05:21:01

When my pacemaker was first inserted, it was because I was having intermittent episodes of complete heart block. My doc described the pacemaker as a seatbelt, there if I needed it, because 99% and more of the time my heart was doing just dandy on its own. 

Fast forward six months, about a week before my first regular interrogation, when I had a stroke and had to have the device put into MRI mode for a brain scan. Well, surprise, it turns out that I was now completly pacemaker dependent. Later my EP showed me the graph where the ventrilcular pacing percentage steeply increased a few weeks after insertion. It starts off flat on the bottom, but then starts curving up pretty steeply and within a month or so is almost flat on the top. Atrial pacing remained minimal. So much for it being just a "seat belt". And, by the way, the settings became WAY more important! If it's only kicking in a few seconds at a time every week or so, having the right max rate etc. doesn't matter much. 

Anyway, there apparently is such a thing as intermittent complete block, which was the reason I got my pacemaker. 

ETA: Quickjraw, I had the same thing happening with excercise pushing me into 2:1 block just as I hit 130, or whatever the default "old lady" setting was that I was initially set to. Not a comfortable feeling to just be gettting going and then suddenly completely run out of steam because your heart rate drops by a third or a half.

Pacing Trends

by simonva3 - 2021-07-20 05:11:02

Elisabet, that sounds quite similar to my situation, (see my graph).  As you describe, when taking exercise (not particularly strenuous in my case) I suddenly feel I have to stop, but strangely the feeling is just for a few seconds, and I can then resume.  My wife often tells me to have a rest for a few minutes, but I don't need to.  However, in another, say, 5 minutes, I have to stop again.

I'm having a nightmare trying to see a consultant, due to mistakes made by my surgery doctor and by the NHS booking service, which has offered me an appointment in April 2022 !!

I'm still pushing the system, but it's really unsatisfactory.

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