seems low

hi all:) just a quick question about settings mine seems very low when i read other peoples settings my high setting is only 120? that seems low doesnt it ...maybe theres a reason for it i had my pm put in for sss and mobitz type II my heart readings were alll over the place pre pm oneday high and next min very low and then heart stopping for a time.. i just dont understand why mines set so low ive been back and had a check up and the docs say pm readings are great no af and only 6% it drops low and pm kicked in and 88% my heart does its normal thing .....can anyone help? thanks so much with love karen xx

6 Comments

Inga

by Tracey_E - 2013-07-03 01:07:43

I know, but that isn't what she was describing so I was trying to keep it simple ;o)

low numbers

by Tracey_E - 2013-07-03 07:07:53

You answered your own question, "it drops low." 120 is a common starting place for the upper limit, they only move it higher if you need it. If you primarily pace for SSS, the important number for you is the lower limit because your problem is the heart getting too slow/stopping. It's likely you beat on your own once you get your rate up so it doesn't matter how high it's set to pace.

Upper rate limit

by golden_snitch - 2013-07-03 10:07:51

Hi!

Tracey, SSS is not only sinus bradycardia or arrest, but can also include tachy-brady syndrome or other fast atrial arrhythmias. I guess this is why Karen said her heart rate was all over the place when she was diagnosed.

Karen, sounds to me like your cardio - as many, many others - did not bother to change the nominal pacer settings, the ones that are already programmed when you have the pacer implanted. 120 as an upper rate limit is a typical nominal setting.

With SSS you might also suffer from chronotopic incompetence, meaning you cannot get your heart rate up when moving around or exercising. Now, if that is the case, then the 120bpm limit could indeed become a problem. To give you an example, when I go running, I need around 130-140bpm for a slow to moderate pace. Your pacer won't do anything above 120 when your sinus node doesn't work properly.

On the other hand, when your sinus node is going too fast, and you are not having a heart block, the upper rate limit doesn't matter - the tachycardia will simply override and thereby inhibit what the pacer is doing; the pacer can only "watch".

Another situation: Your sinus node is going too fast, and you have a block, then the ventricular pacer lead will track the sinus rhythm up to 120bpm, and if it's faster than that, it'll go into a 2:1 block, pacing your ventricles at 60bpm only. This is a safety feature designed for atrial tachy-arrhythmias such as atrial flutter or fibrillation, but unfortunately it works with any rates that are faster than the upper rate limit.

Now, the question is: Do you feel like your heart rate doesn't increase enough sometimes? If you do, then you probably need that upper rate limit changed. However, if you feel fine with this setting, then there is no need to change it. It sounds low, but as long as you're doing good, that is what counts.

Inga

Hart Rate

by SMITTY - 2013-07-03 10:07:57

Hello,

OK, let's start by reviewing the way I think a PM works for us. This way if you think I'm going down the wrong track you will know where to stop reading.

We get pacemakers to increase our heart rate when the heart's natural PM lets the rate get too low. This is done by the PM monitoring the heart rate 24/7 and when the rate from the heart's natural PM drops below the low PM set point the manmade PM steps in and brings it up to the low set point.

Now we will say the upper set point on your PM is 120. Your PM simply monitors your heart rate and when it reaches 120 for whatever reason, the PM steps aside but continues to monitor. It will not add heart beats until it determines that your heart rate is going to drop below 60. In other words the 120 is in effect a cutoff point for your PM to quit increasing your heart rate even when it thinks it may drop below 60 BPM.

To get a PM to increase our heart rate, like say when we exercise, the PM has a feature called a rate response. It also has an upper set point, which the Dr. selects, based on your age and heart condition. The RR can be activated by anyone of several methods, depending on the make and model of the PM.

In my case my PM has an accelerometer and I can check my rate response activity by determining my resting heart rate, then tap on my chest, firmly but not painfully, at the bottom of the ribs on the left side for about 20 to 30 seconds. Then I determine my heart rate.

If I want my PM to have a bigger role in increasing my heart rate I have to discuss that with my dr. I would suggest that you visit the dr for answers to your question.

Good luck,

Smitty

Rate response

by golden_snitch - 2013-07-04 03:07:37

Hi!

The rate response feature is mostly for patients with sinus bradycardia and chronotopic incompetence = patients who cannot get their heart rate up own their own, because the sinus node is just too slow. The majority of heart block patients, on the other hand, doesn't need it since in their case the pacemaker just tracks what the sinus node is doing, and then paces the ventricles at the same rate.

Not sure, if the rate response is switched on in the nominal pacemaker settings; I guess that probably differs from manufacturer to manufacturer. If you want to find out whether it's switched on, just look for the mode your pacemaker is programmed in: Anything with an "R" at the end, for instance DDDR, has the rate response switched on.

Now, with the rate response switched on, and the rates set between 60-150, what the rate response will do is to adjust your heart rate to your level of activity within this range of 60-150. It works with a special sensor or, in some models, with two sensors that measure how active you are. Those sensors react, for instance, to upper body movement or minute ventilation. Most pacemakers offer several rate response settings that can be programmed individually, like the "level of activity" or the "activity daily life" rate or "acceleration/decelaration".

There are a lot of parameters that influence battery life. So, it's difficult to say, if someone with the rate response turned on has a shorter battery life. If that person has, for example, a lower threshold and therefore lower amplitude, he might end up with the same or even longer battery life than someone who's got the RR off, but needs a higher amplitude.

Hope this helps.

Inga

settings

by katbell - 2013-07-04 11:07:45

thanks for that explanation-130 was too low for me-I couldn't do anything physical other than slow walking, and I had shortness of breath-150-seems to have fixed that problem. I have the revo sure scan PM. My question with the settings are...if your settings are 60-150 and you can do your usual activities what is the rate response feature supposed to do? What's it for, does it shorten your battery life? Do you need to activate it, is it automatically turned on by itself? How does that work?

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