Is CLS OK with a healthy SA node?

I had my 3 month CRT-P check 2 days ago. Overall I'm feeling great and have been able to gradually increase the duration of exercise walking. However, when I exert like walking up a slight hill, I have the urge to go faster but it feels like something in my chest won't let me. I didn't know if that's because my heart is not yet strong enough due to cardiomyopathy, or if a change in the CRT settings would help. I have a Biotronik Evia HF-T. The Biotronik rep turned on the CLS (closed loop stimulation). It's a little early to tell, but I think it's helping. In the meantime I've been reading the posts mentioning CLS, and am now wondering if having the CLS on will be problematic since I have a healthy SA node? All the posts I found seemed to be talking about blocks or ablations and PMs. Is it different with a CRT? Or should the CLS not have been turned on? Thank you for any info!

2 Comments

CLS

by golden_snitch - 2014-05-30 02:05:31

Hi!

Let's put it that way: With a healthy sinus node you should not need the CLS switched on. Generally speaking, a rate response sensor like the CLS sensor is for those patients whose sinus node is too slow and does not increase the rate properly when the patient exercises. Heart block patients often have a healthy sinus node, so they don't need the rate response. Now, what happens when CLS is switched on in someone with a healthy SA node? In the best case, it does not interfere with your SA node; in the worst it overdrives what your SA node is doing. Now, that does not do any harm, but it's always better to let the heart do as much of the work as possible on its own (also saves battery). My impression is that most people, who do not need a rate response sensor, but have it switched on, find this problematic as it competes with their own rhythm. But if you feel better...

A friend of mine has a CRT-D. She needs the rate response on, because the high dosage of betablockers she's on to treat her heart failure, has slowed down her SA node; it was working well before, but with the betablockers it's too slow.

Again, having the CLS switched on will not do any harm, and if you feel better now, then you probably really need it.

Best wishes

Inga



Thank you Inga!

by Marinade - 2014-05-30 03:05:11

I was hoping you would reply since you are so kowledgeable about CLS. That's very interesting about beta blockers possibly effecting the SA node. I'm on a very small dose of beta blockers but I must be quite sensitive to them because I have had terrible side effects. I will keep watching to see if I have any problems with the CLS. I'm not sure how I would know if it was interfering with my natural pacing, but if I start to not feel well, I will call the Pacemaker Clinic right away. Thank you so much for taking the time to answer me!

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