CLS, AV-delay, upper rate

This week I've had a stress test. I could not bring my heart rate up higher than 108 bpm, because I get out of breath. I have a dual lead Biotronik Eluna 8. My upper rate was at 120 during the test, the day after they've changed my pacemaker settings.

On previous checkups:
- the AV-delay was made longer to try to decrease the ventricular pacing, this worked.
- my lower rate was set to 80 bpm because of very bothersome PVC's.
-the rate response was made more aggressive because I could not climb the stairs or ride my bike properly.

So yesterday I went back and asked them to lower my base rate to 70. Which they did. They did not want too raise the upper rate higher than 130 though. I was told this could lead to dangerous ventricular rhythms because of the programmed AV-delay.

This comes as a total shock to me. Will I be able to do any kind of sport or keep in shape with a heart rate of maximum 130 bpm?

10 Comments

AV-delay & exercising

by golden_snitch - 2015-09-12 01:09:43

Hi!

If you program a long AV-delay this also limits your max. (sensor & tracking) rate. That's just natural, because the more time you give the AV-node to do its job, the slower the rhythm can get. So, not sure how long your delay is, but if it's very long, you might not be able to reach higher rates.

Theoretically, a long AV-delay can cause some problems, including induction of ventricular tachycardia (due to ventricular undersensing = not detecting your own ventricular electrical activity properly), but this has to my understanding nothing to do with the upper rate that's programmed. It's a general problem with long AV-delays. But overall, reducing ventricular pacing is considered to be very important, and if long AV-delays that actually help to reduce ventricular pacing, would be so dangerous, no one would program them.

I have CLS, too, and my upper rate limit is the max. sensor rate of 160. I do not have long AV-delays since I have a complete block anyways, so no need to give the AV-node time; I'll always be 100% paced in the ventricles. I have no issues with my upper sensor rate of 160.

Best wishes!

Sensor and tracking rate

by Hartje5 - 2015-09-12 03:09:49

Thanks for your comment!

Can you tell me what the difference between the sensor rate and the tracking rate is?

Today I feel very poorly, even walking the dog is difficult. I have al lot of PVC's and in combination with the lower base rate it seems like my cardiac output had decreased.



Sensor & tracking rate

by golden_snitch - 2015-09-12 03:09:55

The upper sensor rate is the max. rate that your rate response sensor (CLS) can achieve. The upper tracking rate is the max. rate up to which your ventricular pacemaker lead will follow your intrinsic (own) atrial rhythm. If you have a heart block and the upper tracking rate is, for instance, set at 160 bpm, then the ventricular lead will follow the sinus node's pace up to 160. But if the sinus node - or any other atrial rhythm - goes faster, it will stop tracking the sinus rhythm. So, in heart block patients the upper tracking rate = the upper rate limit, you cannot go any higher than that.

I remember having had a lot of PVCs, too, when my CLS was set too "lazy". It was adjusting my heart rate so slowly that my heart was throwing in extra beats to compensate - at least that was my explanation. When the CLS response was changed to "high" instead of "medium" and the "resting rate control" was set to be "+30" instead of "+20", the PVCs were reduced. Resting rate control is only for, well, the heart rate at rest, though. You take the base rate, in my case 60, plus the programmed value and that's the max. rate you can get at rest (in my case 90).

resting heart rate control vs base rate

by Hartje5 - 2015-09-12 07:09:46

Thanks for your explanation. I don't really understand the difference between base rate and resting heart rate and how this can prevent PVC's.

The technician changed what I think is my base rate to 70 bpm, and when I don't have all those PVC's you can see that my resting heart rate is around that figure. I've notices that most of the time my resting heart rate is my base rate plus approximately 10-20 beats.

They've set my AV-delay to 260 ms fixed. I don't know why they chose that figure. But I do understand that PVC's can add another 150 ms to the delay time. After a PVC, the parameter "PVARP after PVC" is automatically extended to PVARP (Post Ventricular Atrial Refractory Period) + 150 ms, up to a maximum of 600 ms. Maybe that is why my heart rate won't go up when exercising?

I don't quite know why the technician did not want to raise the CLS response. I'm trying to read the Eluna technician manual. Very informative but not very easy reading material.

Unfortunately my pacemaker technician is not somebody who is used to explaining what en why to his patients. I'm somebody who wants to be informed and understand everything that is going on. Not such a good combination.

Resting rate control

by golden_snitch - 2015-09-13 06:09:18

"Resting rate control" determines the heart rate range you can have at rest. With standard pacemakers/rate response sensors you only have a base rate at rest, the sensor won't give you any other rate when you are at rest. With CLS that base rate can vary depending on how the resting rate control is programmed. Nominally it is base rate plus 20 bpm, so if you have a base rate of 60, CLS can make it go up to 80 bpm at rest, for instance when you have mental stress. This is special about CLS. Other rate response sensors won't respond when you are at rest, but CLS does.

I am not sure that changing this resting rate control to plus 30 bpm helped with my PVCs; as I said, I had the CLS response set more aggressively at the same time, and I'm sure that this helped to reduce PVCs.

Hart rate won't come up

by Hartje5 - 2015-09-14 02:09:19

Thanks again so much. I just did 10 minutes on the cross trainer. I'm sweating and out of breath but my heart rate still gets no higher than 93 and goes up and down between 73 and 93 what ever I do. This is so frustrating.

CLS settings

by Hartje5 - 2015-09-14 03:09:14

I believe I'm in DDD-CLS. The sensitivity is set to "high" (one step higher than normal). The base rate is 70 and my upper rate is 130. The AV-delay is fixed - 260 ms. I don't know about the other parameters but I think its all standard. I've tried tapping the pacemaker to test if it might respond to motion, but nothing happens.

Settings?

by golden_snitch - 2015-09-14 03:09:55

Sorry to hear this :-(
Do you know what your CLS settings are? Could it be that CLS is not on, but the accelerometer is (motion sensor)? If CLS is activated, your mode is either DDD-CLS or VVI-CLS.

Strange

by golden_snitch - 2015-09-14 04:09:54

My CLS response is set at high, too, base rate is 60 and upper rate 160. My AV-delay is much shorter than yours: 150 ms at 60 bpm and it automatically decreases the higher the heart rate is (140 ms at 80 bpm, 130 ms at 100 bpm, 120 ms at 120 bpm and 140 bpm). Have no problems getting my heart rate up to the max. I wonder whether you have that automatic shortening switched on...

No, tapping won't help with this accelerometer. It's always on, but if CLS is activated, the accelerometer is only used when you are at rest to determine the appropriate heart rate; when you exercise, it doesn't work in combination with the CLS sensor.

I understand how frustrating this must be. I have been through lots of frustration with rate response sensors and even with CLS I sometimes end up frustrated.

The bad thing about CLS is that it automatically re-sets whenever you change a setting. That makes it difficult to adjust a setting, test this change right away, maybe adjust it a little more, and so on. Usually, when I have something changed, I end up with three to four days with loads of inappropriate tachycardia and it actually takes more than a week for the CLS sensor to get back to where it was before the setting was changed.

Hope you get this sorted out soon!

I'll give it a week

by Hartje5 - 2015-09-14 05:09:26

I have an holter monitor next thursday. My AV-delay is 260 ms for all rates, so it is not dynamic like yours. Maybe that's the problem! I'm afraid my pm technician will tell me that can't be changed without the percentage of ventriculair pacing going up.

I've read the Eluna 8 has 3 dynamic AV-settings; low, medium and high. All values in those settings range from 75-180 ms, so that is shorter than my 260ms.

The most recent changes were made last friday. So this weekend has not been pleasant. In the middle of the night my heart rate would suddenly go up and I've had a lot op extra PVC's all day long. At first I was nauseated, probably because my base rate went from 80 to 70.

Thanks again for your comment. I'm going to give it one week and if things haven't improved by then I'm going to ask if they'll see me.

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