Pacemakers ability to detect Artrial Flutter


In sept 2018 I got a Biotronic Enitra 6 dual lead PM because of Sick Sinus Syndrome. I also had Artrial Fibrillation and Artrial Flutter that both now have been solved with ablation. 

The Afib was obvious but to detect the Artrial Flutter I was asked to wear Holter and also Thumb-ECG at a later stage.

Afterwards I wonder why I had to do this since I wear a Pacemaker?

Have I missed something here or Is really a surface Holder monitor or Thumb ECG more reliable to detect a specific arrythmia than a modern $$$ implanted Pacemaker?

I will of course ask my doctor at next appointment but wanted your views/experiences too. 




Quite difficult to spot AFlut on EGM

by crustyg - 2020-01-07 10:43:13

The PM doesn't record your ECG/EKG, it can only record the electrical signals that the leads observe - albeit with accurate timing between the two.

So what the PM data shows is A-impulse and then V-impulse, with another A-impulse too soon after and perhaps another.  But the ability to see the detail of the atrial activity - flutter versus fibrillation isn't great - you get a good going flutter at 260 per min and it looks a lot like fibrillation, especially as the atrial lead is often tucked into the atrial appendage.

What PMs should be really good at is spotting atrial-derived tachys.



strange indeed

by Gemita - 2020-01-07 14:37:51

Hello Michael,

yes I too wondered why my EP said he wanted to keep my implanted loop recorder (Reveal Linq) in longer after my pacemaker was implanted because it gave him so much information/detail.  I too thought that my pacemaker was capable of giving the same sort of detail but apparently not.  I am quite disappointed really.  As you say they are expensive and are in place for such long periods.  I thought I could live without those awful external monitors but with arrhythmias I guess I may still have to wear those sticky patches all over my chest from time to time.

Interesting to read what Crustyg has said.  At my last interrogation they were able to tell me the number of Atrial Tachycardia/Atrial Fibrillation events I had had, and the percentage time I was in the arrhythmias and my highest heart rates.  They also recorded one episode of NSVT, so I dont really understand why they wouldnt be able to run off an ECG of an important event like say a NSVT episode ?  Also Michael, I do recall day after my Medtronic implant that the technician doing a check confirmed both Atrial Fibrillation and Atrial Flutter 9% of the time at quite high heart rates, but my heart was very angry at the time due to the trauma of pacemaker insertion. 

So looks like we will still have to stick those patches all over our chests to get some detailed data, unless some better home monitoring becomes available (not sure Kardia Mobile 6 lead is up to the job of detecting Atrial Flutter) and I certainly cannot read an ECG in any event.


by mictre - 2020-01-07 17:20:56

Thanks Crustyg for the explanation.

Thanks Gemita. Interesting the comment from the PM- technician. Could it be that he just assumed a certain % aflut/afib based only upon the artrial rates the PM had recorded, assuming that Aflut mostly has lower rate (?). 

Atrial Flutter

by Gemita - 2020-01-07 19:57:15

No Michael they actually confirmed Flutter during the night when my monitor was bleeping. I felt awful and knew I was experiencing a new arrhythmia, so unlike irregularly irregular AF.  It was really fast (flutteringly, regularly fast) and I was very unstable and doctor told me it was probably caused by unopposed Flecainide (I should have been on a rate control med to slow conduction through AV node but wasnt because of low heart rates prior to PM when in normal sinus rhythm).  On my PM ID card they have recorded patient suffers from Syncope, Flutter, Atrial Tachycardia/Fibrillation with apparently normal heart.

I never have slow heart rates when I go out of normal sinus rhythm, my heart just seems to take off like a horse bolting. But my arrhythmias are not long lasting and have been very quiet of late so my PM is working extremely well.

I can usually tell which rhythm disturbance I am experiencing from my symptoms alone.  My doctors are amazed but I am so in touch with my body. I sometimes wish I wasnt so symptomatic but it has its uses. I do hope you get lots of answers and please post them when you can.  

I would just add that atrial tachyarrhythmias are clearly seen by my pacemaker and programmed to be reported on in my pacemaker log.  Since I would place atrial flutter in the category of an atrial tachyarrhythmia, my understanding is that they have been able to determine the different types of atrial tachyarrhythmias I have including SVT, AT, AF and Atrial Flutter.  However I had the benefit of an ILR Linq monitor implant for three years, so they got valuable info from this no doubt


by AgentX86 - 2020-01-08 08:50:47

Yes, flutter is quite difficult to see, even on a twelve lead EKG. Difficult enough that an ER completely missed it, even though I knew I was in flutter. Like Gemita, I could tell when I was in flutter, in fact I knew it before it could be seen on an EKG, which baffles even my cardiologist.

Pacemakers are very limited in what they can see, and even more limited in what they can record. My PM could send an EKG to my doctor who could immediately tell that I was having bigeminal PVCs but the PM could only record more than five PVCs in a row. With bigeminy, there is a normal heartbeat between each PVC, so it ignored them. PVCs are so common even in healthy hearts that there wouldn't be space to record them all, or anything else.

Atrial Fibrillation and Flutter

by Selwyn - 2020-01-08 13:20:26

The AMS mode ( Automatic mode switching), monitors the excessive atrial activity associated with atrial fibrillation and hopefully atrial flutter ( though as I understand it this depends on how the blanking period is set ie. when there is no chance of reading what is happening in atrial electical activity). Your PM is capable of indicating the duration and frequency of when the switching is on ( due to excess activity) and accordingly you get a print out of atrial tachyarrhythmias - useful to know how much AF/flutter you are getting, however it does not distinguish between the two.

Atrial flutter is characterised by a saw-tooth pattern on the ECG baseline. You need an EKG/ECG to pick this up- hence the Holter. 

On your next PM  check up, look at the AMS readout, it will indicate whether you are having atrial arrhythmias of a fast nature, such as flutter or fibrillation.  Useful if you are taking medication and wondering whether the dose needs to be increased.  Aren't we lucky to have PMs for this?

Vent rate isn't a good way to differentiate between AFib and AFlut

by crustyg - 2020-01-08 15:30:08

One of the challenges/dangers of AFlut is that the electrical signals can be slow enough for every one to pass through the AV-node and trigger a ventricular contraction.  A vent rate of 230-250bpm is SCA territory - well at my age it is.  Before my first ablation my EP doc showed me my Holter recording with 5:1, then 4:1 then down to 1:1 conduction.  Even very young folk with WPW can get into serious trouble at this rate - either rapid onset heart-failure or SCA.  I've seen both in otherwise fit patients in their 20s.

With the usually much higher rate of electrical signals in AFib, the refractory period of activation of the AV-node starts to come into play so you don't see 1:1 transfer of atrial activations down to the ventricles, so it's entirely possible that max vent-rate can be <200bpm.  This inability of the AV-node to recharge the cells beyond a certain rate so that they are ready for the next depolarisation (activation) is the basis of the Wenckebach phenomenon and is actively exploited by some PMs to reduce vent-rate as the box detects an atrial-derived tachy event.  How rapidly the AV-node conducts is partly controlled by sympathetic nerves to the heart (hence the changing conduction ratio mentioned above).

In short, vent rate can be a lot higher with AFlut than in AFib.  A paradox.


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It is just over 10 years since a dual lead device was implanted for complete heart block. It has worked perfectly and I have traveled well near two million miles internationally since then.