Biotronic CLS system

Like 45% of endurance athletes I have an atriopathy. When I lay off the gas for long enough for my sympathetic drive to decrease sufficiently during a workout (coasting downhill on a bike, stopping at a traffic light, taking the skis off to cross the road and then putting them back on) I go into 2nd degree AV block. I feel the AV dyssynchrony as being completely gassed and unable to continue until the block resolves about 10 min later. I was given two options: exercise less or get a pacer. Easy choice. 

During the first week post implant my Biotronik CLS at factory settings paced me at 137 after I had my morning coffee and at 160 (lower rate limit set to 40) during a very easy bike ride. I had that function turned off and the lower rate limit set to 30 (my resting HR is 37). Everything was perfect. After a few months I had them turn the CLS function back on at the very lowest setting because I wanted to give the pacer the ability to "learn" how much chronotrpopic support I might need (I am relatively chronotropically incompetent). After a week I did an easy but scary downhill roller ski session and noticed being paced at 170. My pacer is not supposed to be able to AV pace me at faster than 150, so I was assuming that the terror of the steep downhill was making the pacer track my own sinus rate at 170. This happened 3 times during that workout and once was on an easy uphill, so no terror and no other reason to be that fast. The next day it AV paced me at 100 at rest for 5hours straight. Now I am wondering if I can really interpret the 170 episodes the day prior as my sinus node waking up after a 3 year slumber of if that isn't too much of a coincidence given the malfunction of the CLS system providing inappropriately fast AV pacing even on the very lowest setting. Has anyone else had a similar experience?

2 Comments

numbers

by Tracey_E - 2024-10-22 16:47:02

I'm no expert on CLS but a few thoughts

CLS has to learn you, it never works perfectly right after turning it on

How are you getting these numbers? Monitors are not always accurate with us. 

If you are going at 170, that's probably all you. The pacer is a gas pedal, not a brake. If you go faster on your own, it's just going to sit back and watch. 

Biotronic CLS system

by Heike - 2024-10-23 19:31:45

The CLS is a sensor that responds to stimuli from the sympathetic nervous system in the heart, which can also increase the heart rate during concentration and stress. But in addition, the accelerometer also functions in the background for 20% when CLS is programmed to 'ON'. This could be lead to, among other things, your heart rate going to the upper limit during your downhill roller ski session. Furthermore, the CLS will never give a 100% predictable rhythm because it continu keeps on learning.
 
I am 100% paced and 100% dependent on sensors due to chronotropic incompetence after sinus node ablation. In my case for example, when I still had Biotronik with CLS, my paced rhythm would remain at the upper limit for a while, after I had my check-up appointments with the pacemaker technician, and every time it tooks a week or more before the rhythm calmed down a bit.If I had to rest a lot for a few days, then my rhythm also shot continuously to the upper limit with the slightest things I did. When I had more active days, then my paced rhythm quickly became too slow ... this due to the continuous learning of the CLS. 
A quiet ride on the bike usually ended within 2-3 km, whereby I could still cycle the first part with a reasonable frequency around 120 cycling, but after 2-3 km my rhythm suddenly dropped back to the lower limit, after which I hardly came home. In the end it was not possible for the technicians (also from Biotronik) to get the CLS sensor programmed well for me because of pacemaker syndrome.

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