Chest strap resolution question

Hi all. New to PMC, very glad to have found this site. 71 yr old male, avid runner, 66 marathons and counting. Some conduction issues (L and R) going back more than a decade, but more recently diagnosed with sinus pause. The PM went in last year, pacing only when HR falls below 50bpm - less than 5%. No issues so far. Somewhat frustrated that cardio team cannot tell me when that pacing occurs - whether it happens during a run, while I'm eating (fainted twice, both times while having breakfast), or while I'm asleep. Am considering investing in a chest strap but cannot determine from sales lit whether these have the resolution to detect a missed heartbeat or two. Also have concerns about proximity of strap to PM. Any input would be appreciated. Cheers!




by Tracey_E - 2023-03-04 13:28:56

The strap won't affect the pacer. However, the pacer may affect the strap. I've tried several and was never able to get one to work. I don't think that's going to tell you, though, because the pacer is causing the beats so you are not missing beats, they are paced beats now. An ecg would tell a paced beat but you can't wear those.

Does it really matter? It paces when it needs to so your problem is fixed now, no?

What would you do with the information ?

by IAN MC - 2023-03-04 13:46:37

I echo Tracey's sentiments.

A beat is a beat and a heartbeat triggered by a pacemaker is no different to one triggered by your sinus node.

If you knew the answer would you give up eating breakfast or sleeping or running ?

.... and best of luck for your 67th marathon . I have only run 23 so what do I know ?


Good questions

by BMM262 - 2023-03-04 17:10:39

Thanks for the feedback. Basically, I'm looking for proof that the missed beats are not happening while I run, and that continuing to train for marathons does not put me at further risk. FYI - I ran my 16th Boston Marathon nine weeks after the implant and my cardiologist was OK with that, but I'd still feel better knowing when the pacing takes place. If I could pin down the trigger mechanism, then yes - I might change things. Take breakfast, for example. Swallow syncope (a vagal response) could be the issue, and if I can minimize the pacing by modifying the way I eat, then I'll give that a try. Besides, I'm a technical guy and whenever I figure out what is happening, I want to know why it happens. Cheers!

Missed beats

by AgentX86 - 2023-03-04 17:27:23

Again, what would you do if you found that the missed beats were while you were running?  Stop running?

I'd say, with 90% probability, that the missed beats are while you're sleeping.  You wouldn't be missing many (who cares about one here and there) beats while you're running or you'd feel it and your performance would circle the drain. Your heart rate would drop to 50bpm temorarily because that's where you PM is set.  This would be pretty noticable.


by Tracey_E - 2023-03-04 18:27:35

There is no number that's considered good or bad, but 5% is very low. Pacing doesn't damage the heart. It puts out a tiny signal that mimics what the heart should have done on its own, the heart responds by contracting. Simple process and should have no impact on your running and it certainly doesn't put you at risk.

What leads you to believe pacing while running puts you at more risk? I've never been told that. I pace every beat, and my doctor actively encourages me to work out as hard as I can. I did Crossfit 5x week for ten years, and ran a few miles most mornings before class. I switched to Orangetheory last year because of my joints, heart is still doing great and I'm more active now at 56 than I was when I got my first pacer in 1994. By your logic, I'm at risk? Paced or not, exercise is the best thing we can do for ourselves. If we need to pacer to keep up the exercise, it is what it is. 

This is going to be hard for a technical guy to accept, but most of us never know what cuases our electrical issues. There is no single thing we can put our finger on, there is very rarely anything to be done to fix it other than let the pacer do its job. Stressing over it and overthinking isn't going to give you the answers you want. If there was a way to fix it, they would have tried that before giving you the pacer. 


by BMM262 - 2023-03-05 07:06:59

OK, thanks again to everyone for the input. Perhaps I am over-thinking this, but it may take some time before the old tech guy inside me accepts the fact that something goes wrong and I'm OK with not knowing why.  Am I occassionally missing a string of beats (sinus pause), or is the heart gradually slowing to the point where pacing is required? Is this randomly spread throughout the day, or is it tied to some specific activity - like endurance training? Knowing the answers would help me address preventative measures, if possible. It will be much easier to focus on my run if I'm not worried that trying to maintain a race pace puts too much stress on the heart. If I knew that was the case, then no more endurance training. But I don't want to give it up until I have proof that I need to.

And on that note, I'm still hoping for insight regarding the resolution of a quality chest strap. Will they detect a sudden drop in heartrate that only lasts a second or two? 


stress test

by Tracey_E - 2023-03-05 10:37:47

Have you had a stress test where you run on the treadmill and the doctors watch? That's the best way to see what's going on while running and if you are dropping beats. But you really shouldn't be dropping beats if paced, that's the whole reason we have the pacers is to catch it and fill in as needed. 

You can't prevent electrical glitches. We don't usually know the cause, but we do know the fix.

Why do some cell phones (televisions, earbuds, anything electronic) last years and others get glitchy within a year or two? My daughter and I bought the same model airpods at the same time. We both run about the same number of miles a week. Hers are still going strong, I just had to replace mine. The electrical systems of the heart can be the same way. We don't know why some get glitchy and others do not. 

It's possible that years of endurance training caused the problems. I don't think they have a lot of information on why and how much is too much, but there are quite a few elite athletes that end up with heart conditions. Sometimes they need to pull back, sometimes they can continue training once diagnosed and treated. 

If you are cleared to run, you can run. It doesn't matter if the beats are  paced or not. If your doctor says endurance training is safe, then go train and trust your team. 

Do you have a sports cardiologist? They might be able to answer more of your questions about exactly how much training is safe because they see a lot more athletes than a general practice. A consult with one might help put your mind at rest. 

chest straps

by Tracey_E - 2023-03-05 10:39:28

To get back to your original question, I don't think a chest strap is going to pick up what you are looking for. Esp if paced, it can't differentiate a paced beat from a natural one, and pretty sure none of them are sensitive enough to catch a missed beat here and there. But a stress test will, they'll see the pacing spikes. 

Stress test

by BMM262 - 2023-03-05 14:59:15

You are right, of course, about the stress test, and I will address that with my cardio team when we meet next. And I accept what you say regarding the chest strap. If I am experiencing sinus pause during a run, then my pulse is very quickly dropping from the 130-150 bpm range to <50 bpm, then returning. The idea of using a chest strap to pick that up was a long shot, but worth asking about. Thanks so much for your input. Cheers.


by Tracey_E - 2023-03-05 15:45:43

I also had drops like that, it was fixed with programming.  Ask about rate drop response. It lets the heart come down gradually but if it comes down too quickly it kicks in with pacing to keep it level. The treadmill is the best place to fix this one. That's how mine was adjusted. 

It sounds like right now it's programmed to keep you at 60- one beat per second- when you have sinus pauses. That's not good enough when you are running and your rate is 120. Rate drop response should take care of that. 

Some progress here

by BMM262 - 2023-03-25 07:25:31

Found what I was looking for in the interrogation data. Pacing follows SBR events that occur during episodes of relative inactivity. My pulse hovers just above the PM lower rate limit, but then slows enough to trigger the pulse generator. The event timestamps are very helpful - no correlation to my running/exercise schedule - though I'm still concerned that elevating my HR during exercise may cause it to drop too much during rest. As Popeye once said, "When I works, I works hard. And when I plays, I plays rough. And when I thinks ... I falls asleep." 

You know you're wired when...

You have a little piece of high-tech in your chest.

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