Not sure if my pacemaker is working

May 1st I had a Medronics pacemaker installed that was CRT-P with AV node ablation. The Dr set my BPM window at 60-130. I have had chronic AFib for years and the drugs were no longer working at all so I opted for the pacemaker. I've been in AFib for 5-6 days at least and until today my resting HR has been in the low 60's as it is supposed to be. In fact, everything has been wonderful, haven't felt this good in years. Today I felt odd and checked my BP and HR and the HR was staying in the low 80's when I have been at rest. This evening I'm bumping 100 BPM and not feeling so hot. It's Friday eve now so I won't be able to contact the doc until Monday AM.

Have any of you experienced something like this? The pacemaker is supposed to hold the HR at 60 BPM when I'm at rest, right? What is going on with this?




by AgentX86 - 2023-05-13 00:53:48

No, your pacemaker will keep your heart rate above the lower limit (60bpm). A pacemaker will do nothing for an arrhythmia. A pacemaker can only be an accelleraor. It's not a brake.

It sounds like your Afib is peeking through.  It's not clear how your pacemaker is set up.   An AV ablation disconnects the atria from the ventricles so atrial arrhythmias can't reach the ventricle.  The question, is how do you know that you're in Afib?  Your pacemaker must be programmed in a two leaded mode (AAI or more likely DDD).  If this is a good assumption, when Afib is detecte it must be programmed to a mode switch into VVIR mode.  This mode blocks the atria arrhythmia.  It's likely that the mode switch isn't happening. This Afib is usually detected by a high heart rate. It may be that you're not gettig there so no rate change.

Again, your heart rate has to be w the minimum set.

Sounds fairly normal following this procedure

by Gemita - 2023-05-13 08:17:21

Hello TLH, 

You state:  “The pacemaker is supposed to hold the HR at 60 BPM when I'm at rest, right?”  No, not correct.  A simple pacemaker prevents your heart rate from falling below your lower rate limit, but as AgentX86 says, it cannot prevent an increase in your heart rate or stop an arrhythmia that could be causing an increase.  Also our heart rate is constantly changing even when at rest.  A pacemaker with a defibrillator can shock our heart back into rhythm and stop a fast dangerous arrhythmia but even so, not permanently and we may also need other additional treatments.  I do not believe you have a defibrillator?

Following an AV Node ablation, the lower rate setting is usually set higher, say at 80-90 bpm for the first 6 weeks or so, since this has been shown to reduce any risk of a sudden cardiac event.  I would perhaps ask your doctors again what your lower rate is set at?  Hopefully your lower rate is indeed set higher than 60 bpm while your heart is settling and getting used to being paced?  And let us remember, a normal heart rate can be anything between 60-100 bpm in any case, so even if your heart rate rises to 100 bpm, it could be normal (providing you do not have any difficult symptoms like chest pain, breathlessness or other symptoms that cause concern)?

As you will know, AV Node ablation is a last resort to treat an arrhythmia like Afib after all other treatments have failed (medication, cardio version or a regular pulmonary vein isolation ablation).  An AV Node ablation makes a patient immediately pacemaker dependent since it stops the electrical signals from the top chambers getting through the AV Node node to drive the ventricles, the main pumping chambers of the heart.  By stopping the fast, irregular rhythm of AFib from driving our ventricles too hard, we should immediately feel better especially with the pacemaker pacing us at a steady rate.  I am assuming that you have two ventricular leads only since you had uncontrolled (permanent?) Afib and there would perhaps be no benefit in having an atrial lead?  Hopefully you are now steadily paced in the ventricles and are able to ignore the fibrillating atria, since of course your Afib would still continue after the AV Node ablation.  

Even though your top chambers have been disconnected from the bottom chambers and you should no longer experience symptoms from your Afib, rhythm disturbances can also start in the ventricles following any procedure and this could also be happening and causing some of your symptoms.  (Rhythm disturbances like for instance premature ventricular contractions which can be common while healing takes place).  As long as your symptoms are not too worrisome or intolerable, I would try to relax, rest and keep well hydrated.  On Monday you could speak with your pacing team and explain your symptoms and see what they have to say, or of course get help earlier if you need it?  Good luck and please keep us updated

pacemaker not working?

by tlharrris - 2023-05-13 12:39:32

Thank you both for your responses! I was under the assumption that no matter what the atria did the ventricals would indeed be disconnected allowing the ventricals to beat at their programmed rate.

As far as being able to tell if I am in AFib, I have always been able to tell. I can unfortunately feel it. Since the pacemaker, the symptoms are not as pronounced but I can still feel it. I have a Kardia Mobilel EKG devise but I'm positive I left it at our vacation house. Can''t find it.

My pacemaker has 3 leads. I don't know the reasoning or advantages of having the 3 lead but 3 lead it is.

My HR first thing this morning is at 80. I can manage that as long as the Dr is able to get it back down to where it is supposed to be, 60. At the checkup Wednesday he definitely programmed the lower bpm at 60. He did some voltage tweaking also. In the times before when I was not in AFib my resting HR was in the low 50's. 60 felt fine but I'm not liking 80. I do recall my Dr saying that if something happened the pacemaker would reset itself to 80 and I'm wondering if that is what happened. The 101 bmp from last night is distrubing even though it may be normal. I definitely want the atria disconnected from the ventricals which I thought was the point of the procedure.

The only thing I can do for now is to try and not worry and contact the doc Monday.

In the meantime, I'll most likely live and I will take the advise to rest, mostly relax and water is my best friend. We're going to a concert tonight and I am looking forward to that.

Thank you both for your advise and insights. You have been most helpful and I'm glad I found this website. My son found it and told me about it.


by Lavender - 2023-05-13 16:13:08

I'm a CRT-P owner as well. Mine is two years old. I'm also set 60-130. My AV node stopped on its own-complete heart block. 

As found online:  "A biventricular pacemaker performs in an identical manner as other pacemakers in delivering electrical stimulus to prevent the heart rate from going too slow. The third wire, however, stimulates both the left and the right pumping chambers (ventricles) to better co-ordinate the beating of the heart."

You most likely will live til Monday-and beyond😉. You will feel better as your body and heart calm down from the stress of your implant surgery.  My heart was all wacky for a good while. I don't notice it anymore 😃

Concert? I noticed that I can't be close to the big speakers or it makes me feel weird-like my heart is beating differently. Others here have said they're not affected by it but I sit way back at concerts. Enjoy!!

Paemaker working?

by AgentX86 - 2023-05-13 16:14:41

You've given us more to work from now.  You're correct in that most AV ablations completely separate the atria and ventricles and they're paced indpendently of the atria. With this setup, there are only one or two leads in the ventricles.  There is no reason for an atrial lead at all because the upper and lower chambers of the heart are permanently diconnected, as mine are.

However, in a small (as far as I can tell) number of cases  the third, atrial lead is used in the normal way.  This is apparently used for those with paroxysmal or long-standing paroxysmal Afib and you suggest that this is your case.

If this is true, then your pacemaker is set up as a normal two (three/CRT) pacemaker unless it detects that you're in Afib.  If you are, then it mode switches and drives the ventricles independent of the atria.  The problem, then, is to figure out when you're in Afib.  This is often done with heart rate but your heart rate is "normal" so it's not going to do the mode change.  The pacemaker isn't  going to surpress the Afib sensation because it's still acting as the bridge between the atria and ventricles.

In sort, the pacemaker isn't literally broken, though it could be called "broken by design".

Pacemaker working?

by tlharrris - 2023-05-13 16:53:12


I'm hoping that my heart will calm down as you said. I had heard about loud music/speakers causing problems so I will sit back as far as I can. It's a super small venue and it's a Bluegrass band so it should be OK.



I do indeed have the paroxysmal AFib variety so perhaps this explains the 3rd lead. My doc told me after the procedure but things were kinda fuzzy at that time so I don't remember exactly. I am certainly in AFib and have been for days so perhaps that is why my hr is running at a steady 80 bpm at rest instead of the 60 bpm as programmed. Perhaps it mode  switched?

You all have helped me understand this better and I greatly appeciate all the suggestions and help. In fact, I can't thank you all enough. I live in a pretty rural area and the hosital, such as it is, is not much help. They generally look at you and send you off to Bakersfield. I'm glad I have some place like this that I can go to for help.

For more info on me,

I am closing in on 72 years old. I had been a serious cyclist for years, not now tho. I'm stlll very active and just try to keep going and moving. I'm 5'10" and weigh right at 165. I went on my first hike yesterday that lasted an hour. Everything here is up or down but I never pushed it or really got out of breath.

Thank you all again


Broken by design

by piglet22 - 2023-05-14 08:11:28

I did a bit of design and engineering as part of my day job.

I've lost count of the number of bits of equipment that have failed through design.

A manufacturer or a designer more often than not works to cost. They will cut corners to reduce the Bill of Materials. A typical example is a bit of kit that needs a low voltage to work with, maybe something like a heating thermostat or programmer.

A solid design would use a transformer to drop the voltage. Instead, they use a "transformer less" design. Much cheaper, but dangerous and more often than not, burn out. Honeywell central heating valves were designed to fail.

There used to be categories of component quality. Lowest of all was consumer or domestic. Then there was commercial like office equipment. Next was industrial like robotics. The very top grades were medical, military, nuclear and aerospace.

Hopefully medical equipment like the PM is last.

One point on PM memory, It might use a type of memory called EEPROM. This type of memory has a limited lifetime that might be in the order of 100,000 writes. The PM designer should take that into account and restrict how much data can be stored. Even if the PM had an unlimited battery lifetime, memory lifetime would limit its usefulness.

Lavender. I wonder if you are sitting too close to your favorite band's sub-woofer and getting a dose of infrasound. It could certainly shake your insides up. There is a suspicion that the Chinese and Cubans have used low frequency sound waves to target embassies.


Like you, I cycled a lot, but in Southeast England, it has simply got too dangerous. I'm still looking for the coach that forced me off the road into the gravel.A number of fractures on, I limit the bike rides to strictly necessary. I walk a lot and here in the Southdowns, level ground doesn't exist. Without the PM, I couldn't do any of this. Over 1.5 million steps this year and over 600-miles.

In the UK, getting any sort of medical help is getting difficult. GPs are fully booked for the day by 08:30 in the morning and specialists help is on a very long waiting list. In my town there is an Urgent Treatment Centre. Not an A&E department, but for those minor injuries. I went to mine on Friday last for heel pain, but the waiting time was 2-hours, so left.

Better off going to the vets.

Pacemaker not working

by tlharrris - 2023-05-14 11:42:54


For my cycling, it's all 2 lane mountain roads here so I mostly mountain bike. The roads are just too dangerous.

I'm certainly hoping that the Medtronics units ae seriously long lasting!


You know you're wired when...

Your signature looks like an EKG.

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