Rate Response

I'm hoping for some help here. In my effort to get my dual chamber pacemaker/ICD working for me (it hasnb't for 17 months), I'm going to ask the doctor to try turning off my rate response. I have read posts here and listened to PM engineers on the subject. Based on the information and my symptoms, it may be the answer.

What I really need is the ICD because I have had  ventriciular tachycardias. But the beauty of having a pacemaker as part of my ICD is that if/when I go into dangerous rhythms, my device will pace me out before it it kicks me in the chest. Without the PM, it goes right to the electric jolt most likely after you've passed out (I have never experienced that).

My question is: Will turning off my rate response eliminate the  "pace-out" function of my ICD or affect it in any way?

 


14 Comments

Turning off rate response will eliminate the pace-out feature...

by crustyg - 2019-11-27 20:23:37

...for any realistic fixed rate.

No rate response = totally fixed rate for the PM.  Whatever rate they might set you to, the PM side of your box will automatically generate a pacing impulse every ((60/set-BPM)*1000) milliseconds (as long as it doesn't sense a naturally occurring impulse, when it will immediately restart the counter for the next impulse it might generate).  I don't think *we* know how many intrinsic pulses you generate (i.e. not needing the pulse-generator).

So for 120BPM it will generate an impulse every 500ms unless you generate one yourself.  There's no pacing out in this type of pacing approach.

As has been discussed in some of your previous posts and subsequent comment trails, the PM side of your PM does *NOT* average out a paced rate over a 60s period, it generates each pulse on a millisecond-based timer - whose value is derived from the simple maths stated above.

When the traffic cop gives you a ticket for doing 63mph in a 55mph limit, he doesn't have to follow you for an hour and measure the distance - he merely has to show that for a fraction of a second you were travelling at a speed that *would* have taken you 63miles if you kept at it consistently for an hour.  We merely choose to report that speed as miles-per-hour, but it could as easily be feet per second, or inches per microsecond.  The challenge in describing/reporting terms comes when the rate is quite variable: 3 beats in 4000ms is reported as 30bpm.  And then you have some more beats with a smaller beat-to-beat interval.  Is it wrong to say that there was a time when you were at 30bpm?  Clearly not, but it's also not correct to say that you were at 30bpm for a minute, which is what has upset you in the past.

In practice, for you, turning off rate response might mean a fixed rate of 45bpm, or one pacing pulse every 1333ms.

In the past you've expressed dismay at the high percentage of pacing delivered to your heart.  It's not clear why this worries you so much.  There *are* good reasons to be cautious about over-pacing the heart, but for someone at risk of SCA due to VT/VF (without the ICD) I'm not sure if they apply to you.  Perhaps setting your PM to a fixed rate of 45bpm will give you what you want.  Plenty of folk here with SSS can get along fine at that rate (but we go upstairs quite slowly).

It seems that your tendency to VT is where the focus should be, but without the pace-out feature I think you're going to be into Robo-Pop's 'Jesus-jolts'.

This is a question for your EP

by AgentX86 - 2019-11-27 21:07:55

It's an idea but your EP should know.  You could look up the documentation on your pacemaker.  Your answer might be in there.

BTW, I suspect that these two features aren't connected. I don't see why they would be.

Thanks Crustyg

by Keithwhelpley - 2019-11-27 21:08:17

Wow!  That was an incredible explanation, crustyg. I'm going to reread this several times. I have an EP appointment on the 6th and want to understand everything I can. My VTs are an anomaly, I believe and seem to come when the implanted the device. I had just a pacemaker before and then I got a VT and the upgraded me to a dual chamber PM/ICD. It never worked well. I always have had shortness of breath and moments when I didn't leave the house. After about 14 months I started having repeated VTs -- three or 4 in a row, like it was a loop or something. They happened when I was my most calm. Then my EP dropped my PM from a 60 bpm to 48 and suddenly I felt awesome!!!! Slept well. Could exercise again hooray. But a week later the VTs came back. Three in a row like it was a loop. My EP said he didn't know what more he could do Uuuugh. I'm on Flecainide and that is a whole new pile of side affects. I asked my EP if it was possible I just didn't need a pm. He said "I don't know."  
 

This is becoming a long story with too many turns that started with a misdiagnosis of SSS. So I neither have SSS nor AV block. But I have a PM set in the ads DDDR mode. I believe my device is causing my problems and/or PM Syndrome. But docs don't seem willing to go there. But they can't tell me why I have a PM. "The original doctor must have seen something."  They actually said that 

Flecainide ??

by Gemita - 2019-11-28 06:20:02

I am way out of my depth with anything relating to pacemaker settings but I have been on Flecainide and although it was generally well tolerated, it did cause both a slowing and speeding of my heart rate, more noticeable (the speeding part) after my dual chamber pacemaker implant.  My EP actually confirmed that Flecainide was the likely cause of some of my very high heart rates that he saw during my several arrhythmia episodes.  I too have non sustained episodes of VT.

While anti-arrhythmics help treat arrhythmias they can be "pro arrhythmic" and make some of us worse. This was the case for me with Flecainide and stopping Flecainide has both toned down my high heart rates and also reduced my arrhythmia episodes in general which is such a relief.  I am now only on a beta blocker and doing so much better with my pacemaker. 

Maybe before changing any pacemaker settings you could ask your doctors for a trial period without Flecainide and see if things improve for you ??  Remember too (although I am no doctor) that our medication will no doubt have an affect on our pacing requirements and doses may need to be adjusted over time.  I would also suggest getting the usual basic blood tests to check for any problems, especially electrolyte abnormalities and maybe ask for a Flecainide blood level check because it could build up to toxic levels with poor clearance.  Also no doubt your doctors have checked for coronary heart disease because Flecainide wouldn't be safe in this instance.  What is IMPORTANT I believe is that anti arrhythmic meds should only be taken with a rate control med (AV nodal blocking agent) like a beta blocker or calcium channel blocker to try to prevent pro arrhythmia and I hope you are on a rate control med as well as Flecainide ?? Initially I wasn't on a beta blocker (my fault I didnt listen to my EP) and I now have Atrial Flutter as well as Atrial Fibrillation.

When I first got my pacemaker and my symptoms got worse I extensively researched and questioned my doctors and yes it was finally accepted that for me personally Flecainide was the culprit for my worsening rhythms.  Pacing thresholds may be affected by Flecainide, so please research and question your doctors further.

Good luck

 

Prodding the heart muscle can cause electrical problems

by crustyg - 2019-11-28 06:49:14

There's a recognised issue where prodding the heart muscle can occasionally cause problems.  It's probably worth asking your EP docs if they think that your ventricular lead *might* be increasing your tendency to PVCs which can then lead to VT - if you're unlucky.

What to actually do about it is more problematic, because I think you'd struggle to find any EP doc who would remove your ventricular lead and/or ICD.

Other posts on this forum have discussed this same issue, with one contributor warning again that the association in time between PM+lead implantation and the episodes of VT doesn't prove a causal connection.

Pardon me for being blunt: somehow you need to find an EP doc that you trust - which might start with more detailed information from them to you - and then you have to agree to follow their advice.  Your reported self-adjustment of your flecainide dosage speaks volumes.  Most of us have longer or shorter periods of not accepting that we *needed* an implanted device, and the shorter the time between the initial diagnosis and the implantation the more likely it is that there will be feelings that the device was imposed on us.  I'm like you - I want to understand the reasoning behind every decision, why <x> drug rather than <y>, and I suspect you're just the same.  But no matter our background, ability to research and read and learn about our heart issues, nothing matters so much as experience and we both have to trust our medical advisors to get the benefit of their experience.  They aren't all equally knowledgeable, experienced or willing to spend the extra time explaining what's going on, the treatment options and why they recommend one course over another, and we have to get on with them as human beings.  Very few treatments work as well as they should if the patient has no confidence in the person who recommends it.  Lecture over!  My apologies.

ProArrhythmic drugs

by Keithwhelpley - 2019-11-28 07:08:19

Gemita, like you, I have been researching nonstop since it was clear my device(s) we're making things worse. I have titrated my flecainide down to just less than 25 mg every 24-28 hours. I saw the proarrhythmic affect when my levels got too high. Now, my VTs seem suppressed and I get only minor effects if any. 
 

Regarding metoprolol, I was on it for six months, but it brought my heart rate too low and made me faint. I was taken off of it after my extreme dosing of magnesium brought all my rhythm issues under control. Haven't needed it since (if ever). 
 

my EP has suggested doing another heart study to trigger and ablate my VTs. They tried it when they upgraded my device in June 2018 but were unable to trigger it. That is most likely because by the time my heart study came around, I had been taking extreme doses of magnesium and VTs had ceased being an issue. 
 

I would welcome an ablation over drugs, but I don't want another attempt until we address the elephant in the room -- all this began with a misdiagnosis that has since been debunked by a heart study. Are we just layering treatments over treatments in an effort to get an otherwise functioning heart to function with something it doesn't need. I understand I now need an ICD since I had a avT albeit the result of depleted magnesium, but do I have to have the PM portion set to treat something I don't have? Could that be the problem? 

Thanks for taking time to write. All this has been a big help 

ProArrhythmic drugs

by Keithwhelpley - 2019-11-28 07:08:20

Gemita, like you, I have been researching nonstop since it was clear my device(s) we're making things worse. I have titrated my flecainide down to just less than 25 mg every 24-28 hours. I saw the proarrhythmic affect when my levels got too high. Now, my VTs seem suppressed and I get only minor effects if any. 
 

Regarding metoprolol, I was on it for six months, but it brought my heart rate too low and made me faint. I was taken off of it after my extreme dosing of magnesium brought all my rhythm issues under control. Haven't needed it since (if ever). 
 

my EP has suggested doing another heart study to trigger and ablate my VTs. They tried it when they upgraded my device in June 2018 but were unable to trigger it. That is most likely because by the time my heart study came around, I had been taking extreme doses of magnesium and VTs had ceased being an issue. 
 

I would welcome an ablation over drugs, but I don't want another attempt until we address the elephant in the room -- all this began with a misdiagnosis that has since been debunked by a heart study. Are we just layering treatments over treatments in an effort to get an otherwise functioning heart to function with something it doesn't need. I understand I now need an ICD since I had a avT albeit the result of depleted magnesium, but do I have to have the PM portion set to treat something I don't have? Could that be the problem? 

Thanks for taking time to write. All this has been a big help 

TRIAL AND ERROR

by Gemita - 2019-11-28 12:24:24

Hello Keithwhelpley,

With arrhythmias there is often no right or wrong way to proceed and it is all so trial and error until we find what is right for us but I know your frustration only too well.  

I haven't yet had an ablation for my many arrhythmias, since I have been told it would probably take at least two attempts to achieve a good percentage success rate and with my other health problems, I just can't go there at the moment.  I have had an EP study and I was in AF at the time but hadn't consented to an ablation, so they were unable to perform one.  I regret that now because an EP study is invasive and it isn't commonly done on its own anymore.  If I were in your shoes and you feel in good health, I would get another study done because this would at least give your EP the opportunity of having a good look around and seeing close up what is happening.  They might just find that all important spot and be able to ablate it.

For me personally, my pacemaker and beta blocker is all that I need to live a better quality of life at the moment, so I am happy to leave well alone.  My arrhythmias still crop up regularly, but since stopping Flecainide and Digoxin and getting my pacemaker, I don't feel my arrhythmias quite so much, they are not so long lasting and the sudden collapse and surge in heart rate during my arrhythmias is now being controlled better with Bisoprolol alone.  There are many beta blockers you can try until you find one that suits you, but I would definitely ask about a period free from Flecainide to see what happens.  

Unfortunately as we age, arrhythmias become more common and once we develop the substrate for an arrhythmia it will be difficult to cure.   We may find our main triggers and treat them (triggers like coronary artery disease, hypertension, sleep apnea for example) but it may not be enough to give us a "complete cure".  I have come to terms with living with my AF since I know (at 71) that it is probably not curable whatever I throw at it.  All treatment can ever hope to achieve is symptom relief.  An ablation is certainly more successful than medication (my EP quoted 40-45 % success with meds as opposed to 70-75% with a 1st ablation and even higher 80-85% with a second ablation), so an ablation is probably on the table in the future.

All I can say is I would tread carefully with pacemaker changes;  look at lifestyle, meds first.  Eradicate as many triggers as you can (list them and be honest with yourself!! - I wasn't).  I agree with your expression if I understand it correctly  "layering treatments over treatments" is hardly a good thing, which is why I wouldnt touch your pacemaker settings in an attempt to find a solution.  We are all unique, with our own individual health problems which will have a direct bearing on how our arrhythmias behave.  

I agree with Crustyg about finding a doctor that is right for you, someone you can trust and respect, someone you can have these sort of conversations with.  Electrophysiology (for me at least) is so complicated and I need to have confidence that my doctor will take time to explain all my options in treating my symptoms.  We cannot do it alone.  We need the support of a specialist team.  I hope you will soon find that special fix for you

RR and ICDs

by MrTech - 2019-12-01 09:43:36

Hi Kevin, 

Rate response is an entirely separate entity to your ICDs ability to ‘kick in’. Your ICD can do this various ways before a shock is required which basically centres around your ICD pacing faster than the VT (if discriminators are happy it is VT) to break the cycle. 

Rate response is based around your pacemaker aspect of the pacemaker and has nothing to do with the ICDs kicking in function. 

Rate response is normally only used due to SSS/ chronotropic incompetence where the HR does not increase as it should or at all. 

Hope that helps! 

 

Thanks MrTech

by Keithwhelpley - 2019-12-01 15:51:14

I haven't heard it explaind more simply than that, MrTech. It gives me a clear path. My RR has been  turned on since they installed my device and I have neither SSS or CI. I think we have the answer to my problem. 
 

thank you all for your help  

 

RR

by MrTech - 2019-12-02 03:44:32

You’re welcome.

One can ask why the RR is on.  (maybe it was due to being on a beta blocker at one point).

Thing with RR, if your heart rate works perfect well at going up and down on its own when you are active, then the RR may not kick in that much anyway as one’s HR will be‘getting there first’ and beating the pacemaker to raise the heart rate anyway so won’t be involved much at all. Also depends on how RR is set (and make on ICD). It may just be there as back up. Couldn’t possibly know. 

The atrial HR histogram graph read by the clinic will show if the RR is being used much. 

Of course I’m quick to say I’m merely explaining how these devices / algorithms work and wouldnt recommend anyone change settings on what I say. Obviously people should seek advice of their own medical professionals.. yadda yadda. 

RR by MrTech

by Keithwhelpley - 2019-12-02 18:18:10

MrTech, I always bring this information to my doctors, especially since I can't change my own settings or programs. 

The harsh reality for those of us who have devices is that cardiologists and EPs know so very little about the devices they are so proficient at implanting. That's why its so difficult to get them to listen to their patients. The breakdown comes because while engineers are dealing with diagnosis-es that have verifiable and confirmed pathology, doctors often deal in symptoms, which often are not tied to a diagnosis. Treat the symptoms may be the credo of the latter, engineers need more than that in order to come up with these devices that are for specific set of conditions. 

An example would be if I let my electrolytes deplete. My heart would send out erratic electrical signals that look so much like Sick Sinus Syndrome that the cardiologist calls for a PM implant and a setting that is designed to treat SSS. Problem is, my heart never had SSS. It had depleted electrolytes. Now we have a patient who has since topped off his cardiac electrolytes but now has to deal with the negative effects of a pacemaker with a SSS setting in an otherwise functioning heart. 

The doctor ordered the pacemaker based on symptoms that any doctor through his training and experience would think was SSS. The engineer designed the device and its settings to address SSS and NOT mere symptoms,  just as his education and training guides him to do. 

So it's easy to see where the breakdown is. What is needed is a clinic or silo in which doctors, engineers and patients can go and fix their problems. As it is, we have doctors in their silos; engineers in their silos and patients looking for anyone to listen, hoping they don't drop dead because of something as simple as changing a setting. 

I've given this much thought because I am living it. 

 

TREATING SYMPTOMS

by Gemita - 2019-12-04 01:22:35

Hello Keithwhelpley,

I enjoyed reading your last post and I know exactly what you mean. Unfortunately treating symptoms alone is often the only viable option for patients with complex overlapping health conditions or with health conditions for which frustratingly no cause is ever found.  However treating symptoms alone can never work long term which is why so many of us struggle with our treatment, be it meds, surgical, lifestyle changes. This is a whole new area of discussion and I really dont know what the answer is except to spend more money looking for that elusive cause.

Unfortunately I too do sadly all too often see the practice of treating a patient initially based predominantly on their symptoms alone.  How many of us have taken our health problems to a doctor and come away with a prescription and then later have had to return for further investigations - sometimes with serious consequences?  Many patients through no fault of their own may not have the ability to get across to their doctors what the purpose of their visit truly is, or they may be so confused by all their symptoms and come across as over anxious.  Worse still, they may present  with too many symptoms for analysis and send their doctors looking in the wrong direction.  If only our overworked doctors had more time and resources to spend with their patients on "initial presentation" this might benefit us all in the long term.

As to treating symptoms with a pacemaker, I had to prove clearly by long term monitoring (Reveal Linq implant monitor) of my need for a PM since without the "evidence" - at least that has been my personal experience here in the UK - treatment with a pacemaker would not be approved.  My clinic doctors are also well informed fortunately on the working of the devices they implant.  They work closely with PM manufacturer technicians during patient procedures so I do have complete confidence 

Treating Symptoms

by Keithwhelpley - 2019-12-04 13:31:36


Gemita, thank you for you insightful response. Sometimes I think I'm the only one doctors aren't listenig to. But you're right, most often these smart people have to navigate a multitude of symptoms in a patient that are related to separate health issues. That is why I have been patient with all my cardiologists. But when we reach the point when they tell me they don't know why I feel poorly and why I'm having ventricular tachycardias with no visible triggers, I get more aggressive. If their best educated and experiential guesses accompanied with a multitude of test on my heart leads them to NOT KNOW, can we at least consider what the patient thinks!!! The problem most doctors have in this regard is they don't trust their patients to know or to be so intuned with their bodies that they can feel when their heart skips or when the beat is originating from the ventricle rather than the atria.

I had the good fortune to come across a retired engineer for the company that designed and built my device. He listened to my story and asked, why do you have a pacemaker. He knows what it was designed for. When I told him I was originally misdiagnosed with Sick Sinus Syndrom, he asked, why is is set DDDR. That's not even for Sick Sinus Syndrom. He qualified everything by saying that he isn't a doctor and doesn't have all the information. But he said those two questions are VALID and need to be answered. I have asked and have gotten  no answer. Before I ended our conversation he said don't be surprised if the doctor cant answer them, however. Very few doctors really know and understand pacemakers and their programs/settings. 

While I continue to work with my EP on these issues, I have my eye on Sao Paulo, Brazil. They have a world class cardiac center that has come up with a protocol for determining whether someone with a pacemaker actually needs it. The protocol was developed after it became clear that as many as 20 percent of people receiving pacemakers and ICDs actually need them. I haven't been able to find a doc or facility that will conduct the protocol.

And don't get me started on the drugs. Cardiac patients are subject to some of the most powerful and dangerous drugs developed. And like the pacemaker, their effects and use is not understood by many doctors who prescribe them.

 

You know you're wired when...

You have a 25 year mortgage on your device.

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