Exercise and PM adjustments

I have a dual chamber pacemaker/ICD set for 50 bpm. The EP wanted it set low enough because when it paced I became "symptomatic." He wanted to all but turn it off. So rather than flipping the off switch, so to speak, he put it low enough that I just wouldn't pace. 

Since then, I have gradually returned to my cycling and have become as non-competively proficient as I ever was (minus the long six-hour rides). But now I go through definite periods when my breathing is off. I wouldn't call it a shortness of breath, but rather a resistence when I inhale. And it doesn't keep me from continuing whatever I 'm doing. It's just different and annoying. 

My question is, should I be adjusting my PM as I become more fit because we know a heart becomes more efficient and the heart rate slows? There may be times during sleep when I drop below 50, as has always happened to me. And that may trigger a disyncrony between the two chambers, thereby sending blood to the lungs througn a closed valve (or pacemaker syndrome).

Some Background (sorry but this is a long story)

In Jan. 2017 I went to the emergency room experiencing erratic heart rate. After 4 days of observation, I received a PM for what was determined to be sick sinus sysndrome. After my release and 8 weeks of recovery, I passed out on my bicycle with a ventricuclar tachycardia. A subsequent heart study showed the origianl SSS diagnosis was wrong. But it also showed no apparent need for a pacemaker. But one was reinstalled with an ICD to protect me if I had another VT. The pacemaker was set with the same settings as the first despite no diagnosis. The thinking was the original doctor saw something at the time and there may be an intermittent incompetance that requires pacing.

After about a year I began having repeated ventricular tachycardias. One would start, the ICD would kick in and stop it before I passed out, but then another would start. There would be four in a row and then the cycles would stop, but start again some other time of the day with no apparent trigger. It was both scary and frustrating to both me and all my cardiologists. I was put on a very powerful anti-arrythmic drug, flecainide which is designed to stop VTs but for temporary use because of its power.. And it worked. But with every powerful drugs there are powerful side effects. Mine included, dizziness, a severe shortness of breath, erratic hearbeats. My loading dose was so strong, that one Sunday I though I was going to die because I couldn't get enough air. I stopped taking the drug for three days, figuring if I went into VT, my ICD would stop it. 

During this time my general cardiologist and my EP conducted tests to see what the problem was. They just didn't know and they encouraged me to continue taking Flecainide, which I did in lower dosages. I went to Mayo Clinic. And without conducting their own heart study but conducting an extensive EKG and looking at very good Echo, they diagnosed Left Bundle Branch Block (In all my months and now years, that diagnosis had never come up). I was willing to accept their diagnosis. They were Mayo aferall. They sent me home and told me to wait while they arrange for the procedure. 

I couldn't just wait. I was researching as best I could online all of my new heart problems. Up unitl Jan. 2017 I was perfectly fine. There were no issues at all and inside of three years, I was an invalid and no one knew why. I was diagnosed SSS. When that wasn't accurate, every doctor seemed determined to find a reason for my pacemaker. I was diagnosed with heart failure but I didn't have enough of the signs so that was eliminated. Now I was facing Left Bundle Branch Block. But that turned out inaccurate . One of the extreme side affects of flecainide is mimicking LBBB. 

In my research I read every paper I could get my hands on. I even ordered a textbook for heart doctor students and read the section on pacemakers. On page 1,048 (or there abouts) I found a description of what is known as pacemaker mediated tachycardia (PMT) That's when the pacemaker creates a dangerous electrical loop that can throw patients into a deadly VT. Bingo.That made sense to me. I have a mechanical mind and always felt the VT cycles I would go into was a electro/mecanical  -- sort of like and AC unit or heater short cycling. Starting then stopping; starting then stopping. That led me to research even more. I had all the key search words now. I found paper after paper supporting the concept for. One paper described the death of a youthful, active 50-something man with a PM who dropped dead on a socker field. A review of his PM data showed he had been put into PMT.

With all this information, my doctors wouldn't listen. I was a patient conducting online research. They wouldn't consider it. That made me mad because they were not even looking for an answer and flecainide was diminishing my lifestyle and I knew I was healthy. But I had been put into a category of "heart patient" and every doctor kept me there because the doctor before him/her had put me there. 

Fueled further my their inactivity, I found a recently retired PM engineer to work with me. We got all of my settings and we considered every one of my possible conditions regardless of whether I actually had be diagnosed with it. He quickly questioned my need for a PM, but we both agreed from the start he would not provide medical guidance. He would only speak to me about the PM function. He quickly latched onto a setting that was turned on -- rate response. He asked if I had chronotropic incompetence -- that is the diminished capacity for your heart to regulate its rate. I had never heard that before, so NO, I told him. All he said was hmmm. No direction. 

I went to my EP and asked him to turn the rate response off. He didn't want to. I said: if it wouldn't kill me, just turn it off. He reluctantly did so but said it wouldn't make a difference. Almost instantly, I felt better. I titrated off of flecainide and haven't had a VT since. 

I still have my PM. And I still don't have a diagnosis to go with it. In defference to my EP and cardiologists I'm learning to live with the device. Becasue I had a VT in the past, that makes the ICD important, I suppose. But we have tried to make the PM inconsequential. But as I get more fit, I want to make sure it remains that way.






Rate Response

by AgentX86 - 2020-09-18 16:31:41

Since you were originally diagnosed with SSS,  perhaps your doctors think you sill have it lurking in the background.  But I agree, if you don't need RR you don't want it.  Your EP should have been more than willing to let you try without it.  As noted, it won't kill you.  It may make an active life impossible but you would have known that pretty quickly (before you got to the office door).

Besides this, your pacemaker is most likely programmed with an upper limit, too, to keep your heart rate away from VT territory as much as possible.  You could be running into this, too.  From what I understand, that's not comfortable at all, since you'd lose AV synchrony at that point.

If your doctors are blowing you off like that, you really need to find new doctors.   That's unacceptable.  They often don't like patients to refer to the Internet for medical advice but you're the customer.  If you don't like the service you're getting, "You're Fired."

BTW, flecainide isn't a very powerful drug on the ladder of antiarrhythmics.  It's really one of the first tried and it's up from there (flecainide => sotalol => tikosyn => ameoderone).  They're all toxic but in essentially in inverse proportion to their effectiveness. Ameoderone damaged my thyroid and sotalol permanently damaged my SI node and bought me a pacemaker, after only a few months.

Some thoughts

by Gemita - 2020-09-19 07:13:41

Dear Keith,

I have been following and contributing to your previous posts.  It seems to me that you still have worries about your original diagnosis and your current treatment in the form of your pacemaker/ICD.   You must be exhausted from your continuing search for answers.   Perhaps I know this only too well from my own very personal journey with my arrhythmias, including episodes of VT, and the battles I had to fight to find the safest way forward.  You still seem to be fighting your battle with no end in sight although I note your VT seems to be well controlled, if not stopped, and all without meds and with minimum pacing.  Perhaps you have already found the best solution for you ?

My options for treating my arrhythmias initially were 

.  to treat with a rate control med like a beta blocker, calcium channel blocker

.  to treat with an anti arrhythmic med

.  to treat with an ablation.

Like you I did my research.  Doing nothing was not an option because my tachy arrhythmias like Atrial Fibrillation, SVT and the more dangerous arrhythmia Ventricular Tachycardia needed to be firmly controlled.  A rate control med was my safest option to calm everything down but it wasn’t enough and soon I was on more powerful meds like Digoxin and Flecainide, both of which made my heart rhythm disturbances worse.  Flecainide seemed pro arrhythmic, quickly causing Atrial Flutter to develop.  My doctors offered me Amiodarone and/or an ablation but somehow intuition told me neither option would help and I might come off worse.

I pressed for permanent monitoring.  Reveal Linq implant broke the deadlock for me by giving my doctors more detailed information than short term monitoring could provide.  The nature of my arrhythmias were studied by my doctors and they clearly saw a pattern emerging of falling heart rates triggering my arrhythmias and also causing pausing and syncope.  A dual chamber pacemaker was implanted to treat my bradycardia and to maintain a higher pacing rate to enable me to “safely” take a low dose rate control med like Bisoprolol.  Although my arrhythmias have certainly not gone away, they are now infrequent, and of shorter duration and do not cause major symptoms, so for now I am reassured that I am on the best possible treatment.

Good doctors will always try their best to help us.  They do not set out to harm us with dangerous medication or treatment.  I kept pushing to be treated:  they did not force it upon me.  A doctor I regarded as uncaring initially, turned out to be a very wise man, making me realise that all treatments carry risk, some more than others and that sometimes taking out a sledge hammer to hit an arrhythmia was not always the best approach.  For me an ablation would have been the sledge hammer approach, a pacemaker less so and certainly more effective in treating my condition than all the other treatments on offer. 

Should you be adjusting your pacemaker settings as you become fitter ?  I expect as you place more demands on your body, you may need setting changes, although I would imagine these changes will only be made if you develop symptoms requiring such adjustments.  It is only through trial and error that you will find the best settings for you personally. 

I see you have been working with a PM technician.  I would still try to find a doctor you can have confidence in, who will address all your concerns and be prepared to work with you to get you where you want to be.  But it is not just about "reaching" your goals, it is also about accepting and being happy with what you have at present too Keith and you have come a long way and overcome a great deal.  Short of explanting your pacemaker/ICD, I don’t know what else to suggest since you are clearly not at peace with your devices, although your initial condition for which you sought ER help in January 2017 may still be present, so you may well need them in the future even though they are of limited value now.  Good luck





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