Does RV pacing interfere with chest-strap Heart Rate Monitors

I have a dual chamber St Jude pacer and have been using a Garmin chest-strap heart rate monitor.  I seem to be getting odd measurments of my heart rate (like a precipitous drop in heart rate) when I'm getting paced (at high heart rates).  Is it possible for ventricular pacing to interfere with heart rates measured by chest strap heart rate monitors?


More likely that you are having bursts of an arrhythmia

by crustyg - 2021-05-31 17:42:03

For years I ran with a Garmin Forerunner + chest strap.  Good data but towards the end of my running years I noticed that sometimes the HR value would vanish from the Forerunner display.  I assumed it was poor contact with the chest strap, failing battery, poor connectivity between strap and gadget - everything except what it really was.

I was having bursts of exercise-induced tachyarrhythmias - too fast for the chest strap to reliably detect the QRS complexes and calculate a HR => no data.

I was too foolish/ignorant to stop and feel my carotid pulse, which would have told me the answer.  Very occasionally the same happens with my newer Garmin chest strap (that's ANT+ compatible) if I'm cycling up a mountain and trying a bit too hard (usually a bit dehydrated too) =>HR seems to collapse and I feel terrible =>tachy.  Not smart.  For me my PM paces me very well up to a sensible maxHR, so the loss of HR data is a warning (EP predicts I'll end up in AFib).

For you this means check your pulse by hand and assess how you feel and if you feel bad, stop immediately and after resting for a couple of minutes restart at a lower pace.

To answer your Q: No, it doesn't.

No it does not

by Pinkit94 - 2021-05-31 23:29:09

Hello Paul!

I use Garmin HR chest strap, and I find it's quite accurate even when I get paced (I'm 80% paced). The key is to make sure that there is good chest contact, meaning that the strap is not too lose especially as you sweat. Also I have found that once you have to change the battery it's no longer accurate, but that has been true for all of the HRM I have tried out. I had the same problem with my HR "dropping" after/during hard efforts (I only found out about the drops through my garmin), I brought this problem up to my EP and he reprogrammed my device to DDDR with an increase in my upper limit. That made world of a difference, I have a lot more energy while riding, and my average speed increased by 2mph (in mtb that's a lot). If you know that your garmin is working properly, and you still get odd readings maybe call your device clinic. Best of luck!

Pacer re-tweak and back to chest strap monitor

by PaulSoth - 2021-06-01 08:13:58

Thanks for your feedback, crustyg and Pinkit94.  I will be getting my pacer re-tweaked this morning, back to max HR of 150 (after getting it reset back down to "factory" setting of 120 'cuz I was concerned about getting RV paced nearly 100% of the time).  I'm hoping that I can get back to thrashing myself on my bike, which I haven't been able to do after the reset.

I will use my old Garmin chest strap HRM, instead of the Wahoo optical HRM, while I wait for a new Garmin-Dual to arrive.  And, I will try crustyg's workaround to get more reliable HR data.

I'll let you know what happens. :-)

Cheers - Paul

it can, yes

by Tracey_E - 2021-06-01 09:59:47

It depends on the pacer. I have never been able to get a chest strap to work. I've tried multiple brands, had customer service try to help me troubleshoot. no luck.

You know you're wired when...

Your pacemaker receives radio frequencies.

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