Exercise and near syncope

Hi, I am struggling to understand what happens (occasionally) when I exercise. It appears that when my heart rate exceeds the pre-programmed upper limit (170bpm) and I literally collapse. (I get an immediate feeling of being cold, short-of-breath, weakness, heaviness, and have either passed-out or come in-and-out of consciousness over a few minutes.). I understand that the ventricular rate drops by half if I exceed the upper limit. What I need to understand further is - is this situation dangerous? It happened just last week, and my friends called an ambulance. Apparently I look very grey, was clammy and short-of-breath, and barely conscious, and they were extremely worried. By the time they paramedics arrived I was feeling less awful, just very tired, and the 3 lead ECG trace showed a sinus rhythm of 90 bpm with no paced beats at all (which I find strange). What do I tell my exercise instructors? Should they always call an ambulance if this happens? I need some guidelines. Thanks!

4 Comments

been there, done that!

by Tracey_E - 2015-10-23 10:10:13

No, they don't need to call an ambulance. You are not in any danger when this happens and now that you know what is happening you can easily prevent it from happening again. I would not exercise until your settings are adjusted so first thing to do is call and ask to be seen.

There is a safety feature that detects afib and puts us in an artificial 2:1 block (2 atrial beats: 1 ventricular beat), so it cuts our rate from 170 to half that. If you're in afib, this is great because it prevents unnecessary racing. Unfortunately, the pacer can't always tell the difference between afib and a good workout. If you have no history of afib, they can simply turn this off. Most of your problem will be fixed with that one change.

Most pacers go up to 180. They sometimes don't like to go set them all the way up to 180, but ask anyway. That'll give you a bit more cushion.

Next thing to find out is how high your atrial rate is getting when this happens. I assume you have av block so your ventricular rate only goes up with pacing? If your atrial rate is higher than what the pacer can pace the ventricles (170 now), your heart will be out of sync and you aren't going to feel good. Nothing nearly as bad as what just happened, and it's not dangerous, but it makes it hard to exercise. You might want to get on the treadmill while you are on the pacer computer so they can watch what the pacer is doing real time when you exert. This is super helpful and can save a lot of coming back to tweak the settings.

When you exercise, you'll want to keep your rate under your upper limit. See if you can find a heart rate monitor that works. Sometimes the pacers interfere with the monitors so you may have to shop around, ask to try them in the store before you buy. I went through every brand out there and finally gave up but other members have had good luck with Polar or Garmin. Since I can't find a monitor that works, I just stop and count manually when I get a little dizzy. This has been going on so many years I don't even count anymore, just stop and breath deeply for a bit until my rate comes down, then get back at it. My coaches are used to me stepping aside and taking a quick break.

When you get within 10 of your upper limit, whether you're going by feel or a monitor, ease up until your rate drops a bit. In my case, I developed SVT so my rate would shoot up to 200 (at random, not from working that hard) and got to the point I spent half my workout easing up so I ended up on a low dose beta blocker to keep it down. Now I rarely get over 150 so I don't have to worry about bumping my upper limit anymore.

Hope that helps! If you have more questions, just ask.

Heart rate monitoring

by Sam148 - 2015-10-27 02:10:17

Thanks Tracey, that's very reassuring!
I do have AV block, and have had episodes of SVT and non-sustained VT on occasion, so I am on metroprolol for that. My cardiologist seems a bit confused with my heart - how can someone with bradycardia and complete AV block develop VT?!!

I borrowed a Fitbit HR this morning, for a work-out with a personal trainer. It showed my heart-rate increasing up to 148 bpm, but then "zero" for about a minute. When it came back, it was showing 80 bpm and then quickly climbed back up to around 120 bpm. I did feel tired but not dizzy at this time. My instructor made me stop to check my pulse - he was a bit concerned with the "zero" reading!!

Does this fit with exceeding a 150bpm atrial rate and then going in to the 2:1 pacing mode?

Could the prior collapse have been due to me carrying on exercising in 2:1 pacing mode, or was it due to VT? I feel awful for 2 days following that episode.

I have a pacing check on 17th November, but the clinic refuses to see me earlier unless I go to ED, which I don't have time for. Thanks for any advice.

zero readings

by Tracey_E - 2015-10-27 11:10:20

Every brand I've tried shows 0! I assume my rate is a little higher than that, lol. That's the pacer interfering. If it does that, don't trust the other numbers it gives, either, always count manually. Sometimes it will miss paced beats, sometimes it will count both the beat and the pacer spike so it counts double. My new phone has a hrm function so just for the heck of it, I tried it. My rate was 260! It was probably really only 130 and it was counting spikes as well as beats. Anyway, don't trust technology, just count it yourself.

The collapse could have been either one, or a combination of both. I've always felt better as soon as my rate gets back to normal, not good enough to keep working out but nothing like two days. Did they interrogate the pacer at the time? The pacer records events like that, but it will only record a few before the information gets overwritten. Start writing down day/time any time it happens.

This morning, 0 on the monitor then 80 sure sounds like you hit the threshold to switch you to 2:1. It will go right back up again as soon as it switches out of the mode. That switch happening during exercise is super hard on the body, try to ease up and keep your rate under that if they won't see you sooner than your next regular appointment.

I find it fun outside of a cardiologist's office trying to explain that yes, I have a pacemaker for a slow heart and yes, I'm on a beta blocker for racing. I just tell them my heart's a little schizo :) My GP has a basic understanding of what's going on but is clueless about the nuances of pacing and things like upper limits and modes. Go to any kind of specialist in another field and they'll just stare at you confused. It's important that we can explain it.

Tip when you get too fast while working out, put your hands on top of your head to expand the rib cage, then breath in slowly through the nose, out through the mouth. This is the fastest way to get your rate down. I forget where I learned that, but it works.

Good luck!!!! Don't push it too much til the 17th.

Thanks TraceyE

by Sam148 - 2015-11-03 06:11:01

Thanks for the advice. It's good to know that what I'm experiencing is not too unusual for pacemaker user.

I have tried a different HR monitor today, I couldn't make out the brand (? junju or something!). It seemed a bit more useful than the Fitbit, maybe as it had a chest strap. But, yes, my rate did read well over 200 at one point! I wondered why, as I felt absolutely fine. Your explanation is very reassuring!

I will ask for a treadmill test when I next go to clinic - there may be a long wait though. I had one years ago, which is when the minute ventilation function was turned on and the upper rate limit upped to 170. That made a massive difference to my exercise tolerance. I am a bit worried to have had this collapse after a good few years of no problems while doing Zumba, and wonder if it was VT. I should find out on the 17th, as my pacemaker is set to record any VT of more than 4 seconds duration (I think).

I'll update you later this month. Thanks so much for responding to me. I really appreciate it!

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