Pacemaker stops pacing as I increase intensity of work out

Hi! I started training for marathon last year, it was a gradual slow training process as my trainer knew I have pacemaker. I was also going to the pacemaker clinic several times and they made several tweaks on my pacemaker setting. However, late last year I wasn't able to join the marathon I signed up for because as we started our training for uphill, I noticed I have some fainting episodes. I went back to clinic and they've done a holter monitoring and it showed several SVTs but they said it's not sustained and it's alright. But early this year, I went for hiking which I used to do before but this time it's quite different because I felt really almost blacking out. I went to see my cardiologist and had a stress test done, it showed from there that my pacemaker is pacing well at normal speed but when we reached 3 mins of faster steps/jogging on the treadmill, my pacemaker stopped pacing and my heart is not going up when it should, it stayed less than 100 bpm. The cardiologist who saw me said he needs to asks others first on what to do, so after paying 700 dollars for a consultation, I actually doesn't have a clue on what's going on because the cardiologist/EP doesn't know the answer as well. Hoping someone here has a similar experience or had symptoms like I did as well and can shed a little light. ANd if this means I should restrain myself from doing further physical activity such as hiking or running? Thank you


Pace maker stops pacing.....Regina144

by adalongworth - 2019-04-07 09:33:18

You do not tell enough Regina144 but your experiences are not disimilar to mine.  While not a total answer a contributory one might be that the RF on your Min Ventilation and on your Accerlerometer may be too high (resistant).  I would have expected them to have been considered by your cardiologist/physiologoist but I've been sent on my merry way with a heart incapable of beating anything other than 70 - 74 bpm.  However I didn't pay $700 for it!


by Tracey_E - 2019-04-07 09:56:14

You don't say in your bio why you have the pacer. It sounds like maybe your rate response isn't turned on. That's what rr does, it gets your rate up on exertion when it doesn't go up on its own. It's not a perfect replica of a natural sinus rhythm and it can take a few tries to get it right, but it usually does pretty well with running. 

Was your rate up high then dropped? There are two reasons I can think of for that. One, if you are in av block and go over your upper limit, it can think we are in afib and put us in an artificial 2:1 block. Or sometimes our rate can tank on its own. They pacer has a feature that can prevent that. It'll allow the rate to come down slowly but kicks in with pacing if it comes down too quickly. 

Yes, you should cut back what you do until they figure this out. If your rate is not going over 100 while running, that's really hard on the body and easily explains your symptoms. You feel like you're going to pass out because you are very close to passing out! 



by lefty2 - 2019-04-07 12:22:22

My EP told me that if you have too high a dose of beta-blokers then it will be more difficult to get your HR high. I had a non- sustained VT after running on a treadill which my HR got to 125. He weas surprised I got it that high especially since I was on the maximum dose of Coreg.

Pacemaker stops pacing...

by regina144 - 2019-04-07 18:54:14

Thank you for your insights on this, at least now I have an idea on what's going on and can bring it up on my pacemaker check tomorrow. With regards to my pacemaker, I have a dual chamber pacemaker because of complete heart block. I had this since October 2012. 

During the stress test, at the beginning of the test, as the intensity of the exercise increased my hear rate increased in paced rhythm, so my pacemaker was appropriately following my sinus rate. However, towards the ebd of the second stage of the test, there was a slight abrupt drop in my heart rate from 130 to 95bpm with the development of some intrinsic rhythm and a competition with the paced rhythm. During this event, I started to be breathless and as we continued on, started to feel lightheaded so I asked for us to stop at that point. My blood pressure also slightly drop at that point from 150/90 to 130/90

better explanation

by Tracey_E - 2019-04-08 10:03:45

Ok, so it sounds like you have more going on than just av block. I did, too, almost exactly what you described. I have av block, but sometimes when I exercise my rate randomly tanks. With av block our heart was beating at random before we were paced so if we had anything atrial going on, it was masked by the av block. Fix the av block, now the other problems show up, tho they were likely there all along. They should be able to fix this with settings, esp since they watched it happen on the stress test. 

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