Pacemaker settings

Had a check up today said my lower chamber was pacing at 100% and lower chamber at 84% going back in a couple of days to change settings on pacemaker because Dr said 100% was to high.....has anyone else experienced this ....I have had my pacemaker for almost 3 years



by AgentX86 - 2022-06-07 21:20:14

Your post is a bit confusing (you said "lower" twice).  Is your EP saying that 100% pacing on the lower (RV) line is too high?  You have third degree heart block!   Duh, it's going to be 100% if the heart block is complete.

If the issue is that the upper is 84%, well, it is what it is.  He might be able to bring that down some by raising your paced resting heart rate some.  But why?

If the numbers are the other way or if you the question is that there might be something else, other than a CHB, he should be telling you what it is.  He should have filled you in on what he's thinking about your pacing percentage anyway.

Pacing percentages

by Gemita - 2022-06-08 02:45:40

JimmyandJeremy, Yes your post is confusing, although clearly some of us will need pacing in both upper and lower chamber, sometimes up to 100% in both, so your high percentage pacing figures might be perfectly normal for you.  How do you feel?  If you feel good, then your settings might be appropriate for you.  I agree with AgentX86 though, you need to know why your doctors are concerned about your high pacing percentages - for example, are they concerned about early battery depletion, a problem with a lead, or a worsening heart condition requiring increased pacing support (or caused by increased pacing)?  Ideally I would want to know (1) which settings they intend changing and (2) why?  I would also ask (3) for a copy of any changes they make, in case you ever need to get your settings restored in the future.

If 84% represents upper chamber pacing percentage, one thought is that your doctors might feel that your “upper” chamber pacing is unnecessarily high for you and want to "lower" your Base Rate setting to try to reduce this.  For example, my Base Rate is set at 70 bpm and at 70 bpm I am 100% paced in my upper chamber because my own heart rate is always well below 70 bpm.  Reduce my Base Rate setting to say 50 bpm or lower, my % pacing in the upper chamber may well reduce too, but I feel so much better with a higher Base Rate setting.  Since I do not have any permanent, significant heart block, my ventricular pacing is fortunately minimal and generally only occurs during arrhythmias.

I see from your history that you needed your pacemaker for both complete heart block and a low heart rate of 30 bpm?  What is your Base Rate set at?  I also see that you initially had problems with your settings causing an unexpected increase in heart rates with only minor exertion, perhaps due to sensitive Rate Response settings?  Did you ever get this corrected?  You certainly need answers and clearly so do we to help us answer your post.

AgentX86, it is still a bit early here and apologies if I am confused more than usual, but do you mean lowering not raising paced resting heart rate to reduce percentage pacing?  Please see your comment:   “If the issue is that the upper is 84%, well, it is what it is.  He might be able to bring that down some by raising your paced resting heart rate some.” 

Pacemaker settings

by JIMMYANDJEREMY - 2022-06-08 12:03:27

Yes I see I said lower chambers for both I meant 84% in upper ....Thank for your responses I will ask more questions tomorrow when I get a pacemaker setting check


by Tracey_E - 2022-06-08 12:31:36

While it's good to minimize pacing and let the heart do its thing as much as possible, many of us have paced 100% for years without issue. As agent said, if you have complete heart block (which I do), then 100% ventricular pacing is to be expected. As long as you feel good, it's all good. If he can tweak settings and get it lower, that's great, but if not don't sweat it. 

Reducing upper pacing percentage

by AgentX86 - 2022-06-08 18:27:17

Pacing percentage is somewhat counterintuitive.  The lower the bottom rate is set, the higher the pacing percentage and verse visa.

Pacemakers work by adding a beat by measuring the time since the previous beat.  If a "natural" beat isn't found by then, the pacemaker adds one.  If the "natural" beat is seen, the timer resets, without signalling a beat, then starts the timer for the next beat. If it doesn't see a beat when the timer goes to zero, it adds a beat, then resets looking for the next.

So, lets assume the pacemaker is set for the bottom rate  of 60bpm. The timer would be set for 1 second (1 minute / 60 per minute).  Let's say that the natural heart rate today is 65bpm.  The time between natural heart beats would be 1 minute /  65 per minute, or .92 seconds.  Since .92 < 1, the pacemaker's timer would never expire so would supply no beats (0% pacing percentage). 

Now, assume the natural pacemaker is beating at 55bpm. That's 1.09 seconds between beats.  Now, the pacemaker is set to supply a beat after 1 second.  1.09 > 1, so the pacemaker would supply all of the beats (100% pacing percentage).

Where we get a percentage less than one, but greater than zero, is where the heartbeat isn't stable; sometimes we get a long beat and sometimes a short.  In this case, the pacemaker times out some of the beats and not others.

If the lower pacing rate is raised (less time allowed between beats), the number of natural beats that are shorter than this time goes down. The pacing percentage goes down.

The pacing percentage can be directly controlled by the lower pacing rate.

Edit: I think I was making it more complicated than need be.

More simply, a pacemaker really works in milliseconds (thousanths of a second).  The timer runs so many milliseconds, if it doesn't see a heartbeat by that time, it adds one. The pacing source that gets there first wins, which means that it too fewer miliseconds. Since frequency is 1 divided by time (in seconds), the lower the milliseconds, the higher the frequency.

The pacing percentage is the ratio of the number of times the pacemaker wins (heart is slower) divided by the number of times the heart wins (heart is faster), multiplied by 100%.

Now that's probably even more confusing...

Atrial Pacing percentage

by Gemita - 2022-06-11 04:50:49

Hi AgentX86, thank you for taking the time to provide such a full explanation.  It was really helpful.

I can understand and agree that the lower our own heart rate falls, for whatever reason, the higher will be our need for pacing support, especially if a low heart rate results in inadequate oxygen levels being pumped around the body causing symptoms like dizziness and fatigue.   

I hope we are saying essentially the same thing, but I also believe that a higher base rate setting may also result in a higher demand for pacing, particularly if our own natural heart rate is so much lower than the base rate setting.  If my doctors reduced my base rate setting from the current 70 bpm to around say 40 bpm, this might well see a reduction in my total atrial pacing percentage since my heart would be doing more of the work on its own, especially during the day when my own heart rate might be higher than 40 bpm on occasions.  This would then require less support from my pacemaker, hence a lower pacing percentage would be seen. 

I can see my pacemaker is working continuously to maintain my preferred 70 bpm base rate setting, which is way above my own natural heart rate of around 40 bpm during the day and often falling to below 30 bpm at night. I am now 100% atrial paced at 70 bpm.  



by skigrl3 - 2022-06-18 00:15:50

I went for 1st checkup for pm. Just about 4.5 weeks in. My cardiologist said I am (atrial) pacing at 64%. I asked if therr was an optimal target, he said, "Not really, but for you a 64%" is just fine" , and that its probaby "my normal". Ventricular lead currently doing 0% now which is a good thing. So my point is that I guess these %'s while seemigly arbitrary, are not one size fits all and whatever your baseline is, that percentage range should work best for you.

one hundred percent

by dwelch - 2022-06-25 02:02:06

Like a few others here (and they answered here too).  I have been at 100% for like 35 years, and now I have a biventrical, so both lower chambers are at 100%.  if you have complete (third degree) heart block like I do, then this is perfectly normal.  If that is what you have then your doc should know better, i would be concerned about this doc.  If that is not what you have then still it is not a scary number.   

And no, this does not necessarily mean you are 100% dependent, each time I go in they turn off the pacing for a bit, and I return to my normal rythm, if you look at the EKG or when you ask for your printout if they give you the ekg with that printout you can easily see the heart block...If this is what you have.  I dont die in the chair then come back to live, just feels a bit weird as can the other tests they do.

You know you're wired when...

You make store alarms beep.

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