max heart rate

limits

by Tracey_E - 2012-10-14 10:10:53

Been there, done that! Do you know what your upper limit is? Medtronic has one that goes to 220 but most pm's only go to 180. That's what it can do, not where it's set. They are usually set no higher than 130-140 as an upper limit unless they know you need it higher. If you are pacing at your upper limit, then yes the pm is keeping you from going higher and this is affecting your workout.

Until you find out what's going on, stop when you get that feeling or try to keep your rate a bit lower (150 or so) so you have a cushion between where you work out and the pm's upper limit. A quick interrogation should tell the story. If not, ask to get on a treadmill while hooked up to the computer and let them watch what happens when you run. This can save a lot of trial and error.

Two things I can think of that might be happening

If you have a sinus disfunction like SSS and are depending on rate response to raise your rate for you, it's only going to raise your rate to your upper limit. The fix is setting the limit higher.

If you have av block, your sinus node functions normally so you just need the pm to make the ventricles beat when the atria do. This is what I have. If your atrial rate gets up to say, 200, one of two things happens, depending on your settings. The ventricle can only pace to your upper limit, which sounds like is around 170.

Either your atria (cruising at 200) gets out of sync with the ventricles (stuck at 160), or the pm thinks you are in afib and kicks in a safety feature which puts us in an artificial 2:1 block, it suddenly starts pacing at 80 so it's even more out of sync than the first scenario. This is a good thing if our rate takes off because of afib, it's a huge PAIN if you are exercising. I've had both happen. The first just makes me suddenly really tired, kind of dizzy. The second is going in a blink from feeling great to trying not to pass out.

Do you feel a drop in pulse when you feel bad? In my case, they just turned the safety feature off since I have no history of afib. I also had the second problem :o) (yes, I keep my rep on his toes!) They turned my upper limit us as high as it would go (180) and that worked for a few years. I learned to ease up when I got over 160, trying to stay under 170 so I had a cushion. Then it started getting faster than that so I went on a low dose beta blocker to stop the atrial racing. Now I rarely get over 150.

Hope that makes sense! Best thing to do is write down the day/time it happens and ask about it when you go for your next check so they can look up what happened. If it's not in the next few weeks, ask to be seen sooner and take it easy until you get some answers. It's hard on the body to be exerting when out of sync.