Understanding my pacemaker

Had a Medtronics Advisa DR MRI installed 2 months ago. Diagnosed with carotid sinus hypersensitivity. Doctor says it is set for the following:

Normal use: 60bpm -130bpm

Pacemaker is set to intervene if bpm drops 20bpm and drops below 60bpm. If I understand this correctly if pulse drops from 85 to 65 PM will not intervene. But if it drops from say 75 to 55 it will since the low number is below 60.

I have an occurrence usually once a day. My heart rate normally stays in the 60's, so for the PM to intervene it would mean my bpm dropped into the 40's which to me is pretty low. I have no idea what causes it unless I am putting pressure and not realizing it. It can occur in the daytime sitting in a chair or at night while lying down. Lying down I can understand the possibility, but just sitting in a chair I can't understand. When the PM turns on it shoots my bpm to 100 instantaneously for a few minutes and then bpm slowly reduces back down in the 60's. One of the other settings for the PM is it to push bpm to 100.

A couple of times this week I had occurrences while checking my pulse. Pulse seem to be in the low 60's and then all of a sudden the PM shoots it to 100. Do not understand why the PM turned on with bpm in 60's unless it dropped 20 between a beat before I could detect the drop. For that to happen the drop and the PM detection would have to pretty quick.

First question is am I understanding how it works correctly?

Second question, why is the PM programmed to go to 100? Why not 80 or 90. A sudden increase to 100 is not very pleasant.

Third, with a bottom range of 60 and a 20 bpm allowance before the PM turns on, that would mean bpm could go as low as 40. 40 too low or is acceptable?

Long message, but would appreciate anyone's input.

Thanks.


3 Comments

pacing

by Tracey_E - 2016-05-14 04:05:36

First advice, don't spend all day checking your pulse ;) Little fluctuations are normal and you'll make yourself crazy tracking it all. If you feel bad, count. Otherwise, trust that the pacer is doing its job and resist the urge.

Second, the pacer is always working, always watching, but it only kicks in when we need it. You are looking at three different numbers.

Lower limit of 60. That means one beat per second, it doesn't average over a minute. Any time you go a second without a beat, it will kick in, always, no matter what. That may not always work out to exactly 60 over the course of a minute, sometimes you'll count upper 50's and that's perfectly ok.

Upper limit of 130 can mean two things. One, it refers to ventricular pacing when you are in block where the atria beats but the signal gets blocked and doesn't make it to the ventricles. It will pace the ventricles up to 130 bpm to keep up with the atria. However, it sounds like your ventricles follow the lead of the atria and you don't have block so this number is irrelevant for you. Your heart can go as fast as it wants on its own, the pacer will just watch. So, don't be surprised if sometimes when exercising your rate gets higher than that. Normal because that part of your electrical system is not broken.

The other thing upper limit can refer to is rate response. This means if your rate doesn't go up appropriately on exertion, the pacer will sense the exertion, step in and give it a boost. Up to 130, it won't pace you faster than that. The settings on this can be adjusted and it's not uncommon to take a few tries to get the sensitivity fine tuned for your needs.

20 bpm drops. That's called rate drop and is for when you are chugging along at a higher rate and suddenly plummet. I have that, too. If the rate drops more than 20 bpm, it will kick in with pacing to keep it steady. It's not raising it, it's just keeping it from dropping too quickly. Again, it's going by seconds, not minutes, so it will kick in after a few seconds to level things out. So, our rates can come down slowly after exercise and it won't step in, but if it drops too quickly/inappropriately, it will keep the rate up. Kinda cool how it can tell the difference.

Sudden increases might be you, it might be rate response is set too sensitive, or it could be some setting I've never heard of (I'm just a long time patient who asks a lot of questions and has a super patient doc and SJM rep) but I've never heard of pacing setting that would cause sudden jumps for no reason. Write down the day/times it happens and ask them when you have your check. They can tell if you were pacing at the time or if it was you. Sometimes it takes a combination of meds to keep us from racing/jumping up too quickly and the pacer to keep us from getting too low/plummeting to get us feeling good.

Does that help clarify?

Sudden drop

by BillH - 2016-05-14 05:05:43

The suddend drop is for people whose automatic response does not work all the time.

Most common is when standing up. So if is at 85 and you stand up and it drops to 65 it will kick in to raise it.

But if your heart rate slow declines below 60 it will trigger to keep it at a minimum of 60.

Either OR condition will cause the PM to respond.

PM goes to 100 when triggered.

by jamesyboy - 2016-05-16 02:05:36

My PM is triggered when two conditions are met:
One, a drop of 20 bpm. Two, the drop causes the heart rate to go below 60. When those two conditions are met the PM is triggered.

When it is triggered it instantaneously shoots my bpm to 100. After a few minutes the PM starts to slowly decrease the bpm and turns off when I guess it reaches a normal level. According to my doctor the PM is set to do that. I kept getting 100 bpm when these events would happen and I wondered why always 100. It's because the PM is set to go to 100 when an event occurs.

My assumption had always been that the PM would not allow the bpm to go below 60. If it did, it would bring it back up to 60. So I was surprised when I found out it was set to go to 100. I thought I had afib, so went to see the doctor. She said no afib. The PM is set to do that. She did not explain why 100 and I didn't think to ask at that time.

I do not know what my BP is when an event occurs, but was wondering if my BP drops significantly at the same time my bpm drop could that be the reason for a 100 setting. To get the BP up quickly.

The sudden increase to 100 bpm is not pleasant. You feel a rush and head starts to throb somewhat. Sometimes get a slight headache.

Before a PM I had no symptoms other than when pressure was put on one of my carotids. Main reason I had it put in was maybe during sleep my pillow might be putting pressure. One doctor said that was a possibility and that because I was sleeping I would not be aware.

Apparently I do have a problem since the PM is being triggered. It triggers one to two times a day, so guess I have to learn to live with it.



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