heart monitoring

I've had a pacemaker now for 1.5 months and I think my pacemaker needs a little tuning to get it right.  But I've noticed something odd. When I wear a heart monitor (in this case a chest strap that transmits to my phone), I'm noticing something unusual.  In particular, when I’m working out, the monitor is indicating ~ 50% of what it should be.  For instance, I’m on a stationary bike and typically my heart rate would be in the 130 range, by my heart rate monitor is indicating 65.  I’m thinking that the heart rate monitor is measuring what my heart is actually creating and cannot sense pulses induced by the pacemaker.  Anyone know if this is the case and or experienced the same thing?  I’ve tried 4 separate monitors/types and have the same results and I can’t believe that if I’m working at 90% of my capability that my heart is only running at 65 bpm.  After being on the bike for 45 min, the rate will sometime jump to the 130 range so all things being equal, I question what the heart rate monitor is actually measuring.

6 Comments

Counting

by AgentX86 - 2018-08-12 18:23:40

Try counting your pulse manually or use a BP cuff or pule-ox meter (they're cheap on Amazon) when you think this is happening. We don't have any information about you so it's going to be difficult to guess what's going on.  If you do have a block, like this, your EP is going to want to know.  It's unusual, though it does happen.  I'd bet on a more obvious problem, though.

pule-ox meter solution

by Dakotamick - 2018-08-13 09:08:40

I had no idea how inexpensive these items are.  Given I need to take a measrement during a workout, this is a an easy solution.  I have made comparsions using the cuff and always got the same reading as my chest strap but not under conditions where I'm actually enagaged in physical activity.  This is a solution that uses a alternate method so will try it.

One answer

by Gotrhythm - 2018-08-13 11:49:01

I don't have an explanation. I suspect there might be several possible scenarios which would produce the same readings on epuipment.

My base heart rate is set at 70. Fequenly my pulse as measured by my pulse ox is half or 35. Other times it is in the low 60's. I have frequent PVCs. A PVC is a "normal" heart beat, but since the ventricle is contracting a litte bit early, before the ventricle has completely filled, it's a less efficient beat. It's weaker.

Sometimes my heart will begin to beat in a rhythm of one beat, one PVC, one beat, one PVC etc called bigemeny. When that happens, instead of the normal 70, my pulse ox will read 35.

My heart is still beating 70 times. But half the beats aren't strong enough by the time they get to my fingers to register.

Pulse Ox

by AgentX86 - 2018-08-13 23:23:03

Because of Afib/flutter, I had to watch my heart rate pretty carefully. A couple of days before I went into arrhythmia, my heart rate would jump by 50%.  I also had to be very careful when exercising (I do 2-1/2H a day on a treadmill) so my HR wouldn't get too high.  My FitBit would occaisionally show really high rates and I had no way of knowing if they were real (it is tough taking a measurement manually when you're walking).  The Pulse Ox meter allowed me to tell when the FitBit was lying to me. 

Gotrhythm may be onto something and there are any number of other issues that will cause these symptoms, however it would be good to eliminate the obvious first. If you can get confirmation, then you can buttonhole your EP with "evidence".

pacers wreak havoc on monitors

by Tracey_E - 2018-08-23 21:00:30

I've never found one that works for me. Either the pacer interferes and it shows no heart beat, or it picks up pacer spikes as well as beats so it shows way too high.  The one on the treadmill at the gym is all over the place, it'll show rates from 30 to 200. I gave up. I keep a pulse oximeter in my gym bag but never bother using it, just count manually if something feels off. If I feel strong, can talk but not sing, I assume my rate is good. 

Update

by Dakotamick - 2018-09-12 09:21:46

The Pulse Ox meter is an excellent idea and for ~ $20 a cheap way to get stats and alternative information on how your heart is actually doing. 

I have been using a chest strap to monitor my heart, it has two sensors which detect electrical activity from the heart.  In my original post I was trying to correlate the fact that my heart activity as monitored by the chest strap was ~ 60 when it should have been ~120.  So basically I’ve just completed a treadmill test and I can confirm that when the pacemaker kicks in the chest strap monitoring is inaccurate.  I’m talking about numbers that are off by 70% and in fact when the pacemaker is running at around 140, the chest strap may only register 40.  This kind of makes sense as the pulse induced by the pacemaker (electrical field) is slightly different and I believe that the chest strap and for that matter, any of these fitness type tracking devices have difficulty in measuring heart rate.  I’m also able to verify this with the pulse OX meter during heavy exercise.

Is this useful?  Tells me more about what’s going on in real time, forced my doctor to relook my settings and am now working to get better “tuning.”

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