Upper Limit

I went for my very first pacemaker check yesterday and it was a very interesting experience to say the least! The representative from Boston Scientific (I have a guidant Ultrua 60) basically said she could set my pacemaker at anything I wanted which I thought was interesting. Anyways I asked her to explain any changes she made and she changed the voltage from 3.5 to 2.5. the lower limit was changed from 60 to 55 at my request. I asked her about the upper limit and it is set at 150. I asked her what happens if I exceed that limit and she said the pacemaker would stop participating in pacing. I run long distances and the last 2 weeks on my 9 mile runs I have felt short of breath and struggeld after the 6 mile mark. I am not sure what my pulse rate was because I do not wear a HRM. (I assume if I am still moving and breathing I have a pulse so I don't worry to much about it) SO I guess my question is, what happens when you exceed the upper limit of your pacer? She never really answered the question in a way that made any sense to me. She offered to turn it up but since I truly don't understand the upper limit setting I left it alone. I paced 51% of the time atrial and 14% ventricle if that helps any. Thanks in advance!

12 Comments

Very similar experience

by COBradyBunch - 2009-10-13 01:10:17

When I had my first check I went through a lot of the same things. We 'negotiated' rates, with a lower rate of 50 since my RHR would often drop below 60 but from what I could tell never below 55 unless I was going brady. My high rate was actually turned off since I can go beyond my theoretical max, particularly climbing on my bike (Mt. or road) and I have no problems getting my HR to respond upward, just a problem where it can actually drop to zero from time to time for what I call 'heart naps.'

Anyway just had my 3 month check and I am pacing at less than 1% (close to zero per my tech) but they did see I do sometimes get out of rhythm between upper and lower chambers (my aorta seems to want to go faster than my vent) and she said the stats say this is happening almost daily but that it is a normal SSS condition and as long as it isn't bothering me that they probably won't do anything about it. No episodes went for more than 45 seconds but she said for more info I will get it when I see the doc in two weeks for a follow up on my check.

The good news is my pacer should last at least 10 years given my next to nothing usage. That was really good news since surgery and I never seem to get along (and I have had three knees, a shoulder and a few others related to Sports Related Injuries).

Thanks!

by Drin6969 - 2009-10-13 01:10:22

Thanks for all your comments, it helps a ton! My heart rate did go up on it's own before the pacer but never exceeded 120 even at high intensity. Prior to my surgery my EP said the rate response would increase my HR past that threshold. I made an appointment with my cardiologist for next Tuesday to explain my readings and ask him about the upper limit. I actullay have not seen him since my surgery. I now know what questions to ask! I didn't know they could tell if I was bumping my upper limit from the report and the rep did not offer that information.

Carolyn- I have only had my pacemaker since September 1st. Mine was set at 60 because that is what the factory set it at, lol. I no longer get dizzy or pass out, so for me it is an awesome pacemaker! I would agree with TraceyE, it is probably not the brand of pacemaker, but the people who make the adjustments that matter the most.

tuck3lin

by golden_snitch - 2009-10-13 01:10:49

@ tuck3lin:
is there any reason why your heart rate shouldn't drop below 50 bpm at night? i'm a bit staggered that you got a pacer for that because a heart rate in the 40's at night normally is nothing to worry about, and it's - at least according to German guidelines - no indication for a pacer at all. if it was during daytime and would make you feel dizzy or something, ok, but a pacer because of the heart rate dropping into the 40's at night really sounds a bit odd. did you have any problems because of that?

just curious, no offense intended.

best wishes
inga

For Inga

by tuck3lin - 2009-10-13 07:10:12

It wasn't really for a HR in the 40s, it was for the "pauses" that the cardiologist spotted on the holter test.

Long story made short. I went to the hospital because I was having a lot of PACs (hours on end). That wasn't the first time, but it was definitely the longest run I had ever felt. Even my wife could sense them, without telling her what she was looking for, when she put her hand over my chest and felt my heart beat. Somewhat scary at the time. Everyone I met in the hospital told me that PACs weren't really a big deal, but the doctor decided to admit me and keep me overnight for observation. The next morning, I did the usual stress test and echocardiogram, which both turned out great. Just as a precaution, the cardiologist decided to send me home with a 24 hour holter monitor.

The first time I did the holter test, I had about 3000 PACs. Of no concern, says the doctor. Of concern, though, were six separate occurrances (such a low number, but significant) where my atrium contracted but my ventricle did not contract in response -- an indicator of A/V heart block. The longest of these was for about 5.7 seconds (four missing beats), followed by a beat, and then another 3.9 second "pause". That is, during that period my atrium beat normally, but my ventricle only contracted once in 10 seconds. Not good, says the doctor. All of these "pauses" happened at night while I was sleeping and only when my bpm got below about 45. I never really knew they were occuring, only that I was sleeping really, really good. :-)

Just to be sure this wasn't a fluke, and at my request, we repeated the holter test for 48 hours a week later. The PACs were virtually gone by this time, but the pauses were still there, always at night, and always when my bpm dropped below about 45.

So, after hearing that the PACs were "no big deal" in the hospital and that the echo and stress test were great, I was very surprised (alarmed) to have the cardiologist recommend a pacemaker. After some introspection, a rather long discussion about what it all meant, how a pacemaker might alter my lifestyle, assurances this wasn't all random and really an actual heart problem, pluses and minuses of having a pacemaker, etc, etc, I decided to go with the doctor's recommendation (with a lot of prompting from my wife, who when she found out about the pauses subsequently kept nudging me every night while I was sleeping to see if I was still alive).

To sort of catagorize this, my A/V block only happens when my BPM gets fairly low. And, that only happens at night when I am at rest. Consequently, I am only pacing at about 1%. During the day, my heart beats in the normal range of around 60-80 bpm and when I exercise, it rises and falls normally in response to activity. At this point in my life, the PM is more of an insurance policy that really hasn't affected my life style much one way or another. I guess I am fortunate in that respect.




Twin Brother

by COBradyBunch - 2009-10-13 08:10:14

OMG you just told my story with only two variations. 1) I never Holter Monitored because I did manage to black out twice in three months and on the second event they decided to admit me over night. My 'pauses' occurred either while sleeping or while going to sleep in the hospital and one was long enough for a crash team to respond to my room. 2) my PAC's didn't show up until AFTER the PM was implanted. Everything else is the same, the negotiations, the research and even my wife nudging me away to make sure I was still beating (even after the implant). She is an RT and thought I had sleep ap at first but she says now that I have the PM the 'stopping breathing episodes' have stopped which she figures were actually times when my heart had stopped beating.

Anyway, welcome to the club and it is great to have a twin brother from another mother. Just had my three month (actually closer to 4) checkup today and all looks good. Hardly doing any pacing (<1%) and except for the PAC's which seem to visit me regularly but none have lasted more than 1 minute according to my pacer everything is good. Back to exercising and working out on a regular basis anywhere from 80 - 95% of my theoretical max so the heart seems in good shape, just damn screwed up wiring job.

limits

by Tracey_E - 2009-10-13 10:10:00

How limits affect you depends on why you need and how you use the pm.

If your rate goes up normally with exercise and you only need to pm to keep you from dropping too low, such as SSS, then your upper limit is irrelevant because your heart beats on its own and you aren't pacing at faster rates. The pm won't prevent you from going faster than the upper limit because it can't slow you down, it just won't pace you higher than your upper limit.

I pace ventricular, my atrial rate is more or less normal and the pm is there to make sure the ventricles beat when the atria do. So, if my upper limit is 150 and my atrial rate gets to 170 or 180 with exercise, the pm will only make the ventricle keep up up to 150. This causes the symptoms you had.

The other way to reach the upper limit is if you pace atrial and use rate response. RR senses that you are exercising and raises your rate for you when your heart doesn't go up enough on its own. It will only raise your rate as high as the upper limit.

They should be able to tell from the pm report if you are bumping your upper limit and how much you are pacing at your upper limit, if the number is high then they should raise the limit to give you a cushion over what you need. Another way to know for sure is get on a treadmill and let them watch, what your heart does with exercise then they can tell if you need rate response adjusted or the upper limit raised.

Love your attitude about the HRM :o) I've never been able to find one that works, though I do stop and check my pulse when I get lightheaded while working out. I'm almost always at my upper limit (it can't be turned up any more, I'm at the max for my model pm) so I ease up a bit til my rate drops again.

Carolyn65

by Carolyn65 - 2009-10-13 10:10:05

I am interested you have a Boston Scientific Altrua 60 PM. I read from our fellow PM comments they have mostly Medtronics. I have only seen one other comment from someone who has Boston -----. I had my ablation/PM implant, Boston Scientific Altrua 60 on 10/02/09. I have only had it about a week, but so far, have not even noticed it the "implant". I do not feel any signals, etc. I am not an active person so can not answer/help with your original comments/questions, but I am very interested in how your Boston "energizer bunny" works for you and your body over the length of time. All I know is the tech sat mine @ "80" because that was what I was before PM & "they" will leave the PM @ 80 for 3 months after the PM implant. When I go back in January, then they will do more I am sure. Any comments or do you have anything which might have me understand more? I understand this Boston ----- is really good, what do you know? ( :

upper rate limit

by golden_snitch - 2009-10-13 10:10:06

Hi!

If you exceed the upper limit of your pacer then it's either that your heart rate will not go above this at all or, if your own rhythm can go faster than this upper rate, it will. Your pacing percentages show that you still have a good rhythm, about 50% of the time your atriums can do well without the pacer, and most of the time your ventricles work without needing pacing. Now, what it doesn't say is when you need the pacer and when not (more at rest, more when exercising?). Before you got the pacer were you able to run, did your heart rate go up?

Anyways, your pacer's rate response can be tweaked a lot. It works with two sensors, motion & minute ventilation, and there are lots of possibilities to adjust it to your needs. It's a bit tricky and might take some time, but don't give in until you feel well when running.

If I were you, I would probably have the upper rate turned up a bit, I think 150 bpm for running might not be enough (in case your own rhythm is even slower than that). What might also help for the "fine tuning" is to get a holter monitor and run with that. That way the doctor could see best what happens with your heart rate when you are running. Don't let him do a bicycle ergometry because the rate response won't react the same way as when you are running.

Best wishes
Inga

Carolyn

by Tracey_E - 2009-10-13 10:10:47

They're all good ;o) Really. There are different models and manufacturers and they all have different bells and whistles, but most of us will be fine with any brand pm. Boston is the smallest of the three manufacturers in the US. Medtronics is the largest. I have a St Judes.

This is just my personal opinion, but the rep/EP we have is more important than the brand of the pm we have. They'll all keep us alive, but it's the fine tuned settings that truly make us feel good, and that's the people programming it not the hardware to a large extent.

Upper limit setting again

by tuck3lin - 2009-10-13 12:10:05

I should also mention that, in my case, rate response is also turned off, as my heart rate increases with exercise, as it should. So, my only setting is to assist with bradycardia when I fall below 50 bpm.

Upper Limit Setting

by tuck3lin - 2009-10-13 12:10:58

I have a Medtronic Adapta PM. The reason I have it is mostly for dropped ventricular beats that were occurring at night when my heart rate fell into the 40s. I have some PACs and PVCs every once in a while, but lately not that often. During the day and during exercise, my heart seems to beat as it should without any PM assistance. I am 51.

When the technician did my last PM check, I asked him about the upper limit setting and how that worked. As he explained it to me, there are different "upper limit" settings. One is for correction and one is for data capture. In my case, the corrective upper limit was completely turned off (since correcting runaway tachycardia was not the reason I have a pacemaker); that is, my pacemaker is only programmed to correct for bradycardia. But, the upper limit for data capture was set to capture (record) any times when my heart rate exceeded 160 bpm.

He then noted that the pacemaker data he downloaded showed several times where my heart rate was in the 170s for a couple minutes at a time, and sometimes peaking in the 178-183 bpm range. I asked him if these were happening between about 12 PM and 1:30 PM. He looked at the data again, and said that was exactly when it happened (12:54 PM on one day, 12:23 PM on another day, etc). I explained that, well, I work out at lunch several times a week usually by running 3 or 4 miles on a treadmill, and these rates were most likely when I was peaking on my workout.

His response was that if I was someone that hit the gym on a regular basis that there was no point in having the upper limit (data capture) set only to capture the fact I was working out, so he bumped the PM setting up to 180. That way, the PM now only captures data for more extreme tachycardia, if it were to occur (even though the PM isn't set to do anything about it right now). He said that by not using the PM to capture data that isn't really useful, it will probably extend the battery life by 3-4 months over the life of the device.

The point is that when the technician is talking about the "upper limit", there might be more than one. You might explore that a little bit on your next visit.

Limit settings

by ElectricFrank - 2009-10-14 01:10:23

If you have AV block (heart block as some call it) the problem is a disconnect between the atrium and ventricles. You atrial rate is controlled by your natural pacemaker, but the ventricles don't get the message. The block can be complete or intermittent. For this condition you don't need Rate Response turned on so its settings wouldn't be an issue.

The upper limit in this case is called the Upper Ventricular Tracking Rate. As your heart rate increases the time between beats get shorter. The upper limit monitors this time interval and when it becomes short enough to cause your heart to exceed the upper limit it skips a beat. Since the heart rate isn't perfectly even, this starts to happen erratically causing an uneven heart rhythm. As you keep on pushing it the effect is for your heart to only contract on every other beat. If you were wearing a monitor it would show your HR going up to 150 and then dropping to 75. This is not a good situation. At a time when you are exercising at a level that requires greater than a 150 HR to supply blood to your body your heart is beating at 75. This is what is causing the shortness of breath and feeling of struggling.

I had this problem in my early days with the pacer. They had left my upper limit set at the factory default of 120 and all I had to do is walk briskly to feel it. My approach has been to have them set mine to 150 (I''m 79 yrs old) but I don't push it up there. I try to stay around 135-140 max, but if I get it up a bit higher is doesn't get in the way. At your age you should be able to handle a higher setting. One thing that tends to happen is if I get up to 140 and then stop on the trail for a break my HR continues to climb a bit before dropping. Again, I don't like to have the pacer limiting me. Like I told the cardiologist, if I am trying to outrun a bear I don't want my engine missing.

By the way I suggest avoiding pushing it until you get it set higher. It's not good for your body or heart to short change it on blood flow.

frank

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