Pvcs and AF

Can a pacemaker tell the difference between PVCs and AF?



PVC's and PAC's are a Problem

by Swangirl - 2019-11-24 20:11:05

I'm not sure if I can answer your question since I don't have AF.  However, I am aware that my device mistakes PVC's and PAC's for my heart beating and then the PM doesn't fire.  This will result in a "pause" in my rhythm.  There isn't much they can do to correct that problem.

I would hope so !

by Gemita - 2019-11-24 20:30:57

Hi Liz,

As AF is an irregularly irregular rhythm in the upper chambers and a PVC is an extra heart beat that begins in the lower chambers of our heart, I have no doubt that our pacemakers can tell the difference, especially if the pacemaker has been programmed to report on both these rhythm disturbances.   My pacemaker I believe is set up to ignore ectopic beats coming from both the lower and upper chambers and is only interested in following arrhythmias like SVT, AT, AF, Flutter and VT.

At times I have a very high burden of ectopic beats and these invariably lead to worsening rhythm disturbances including AF.  It is known that PACs can lead to AF and I therefore believe that our doctors should be more concerned and not be so ready to pat us on the back and tell us not to worry about our benign ectopics.  I may ask my pacemaker technicians if they can monitor my ectopics for a period to determine their true burden.

Maybe ask your PM clinic for the percentage time you are in AF and the % time you are having PVCs. This would confirm whether your pacemaker is set up to track both rhythm disturbances.

Why did you ask the question Liz?



by pogerm1 - 2019-11-24 22:30:06

I have been told by the pacemaker clinc that i have been in and out of AF, i have asked if the pacer can tell if there could be another arrhythmia, she said no.  I have had AF for around 20 years but I would get AF every few months and it lasted around 12 to 24 hours.  I knew when I was in AF and when I was out of it.  This past month it is different I am not as sure but it isn't quite like AF so I am wondering if there is another arrhythmia.  I have an appt. the second week of Dec.  with my EP, they also scheduled me for a pacer checkup the same day, so hope to get some answers  They also want me to take an EKG monday.  Thanks for your answers


Pacemaker check and EKG

by Gemita - 2019-11-25 03:57:01

Hi Liz, 

hopefully your PM check and EKG will show them if there is another significant rhythm disturbance present. The EKG though is only a snapshot of what your heart is actually doing at the time of the all too brief period of monitoring so it will not pick up a rhythm disturbance happening only intermittently, especially if it is not happening at the time of your EKG check.

My pacemaker checks have clearly shown rhythm disturbances like AF, SVT, Flutter, Atrial Tachycardia and more worryingly, recently runs of Ventricular Tachycardia, but there are specific requirements that have to be met for these arrhythmias (like duration, speed of the arrhythmia) before my pacemaker will report on them. I fortunately can mostly tell the difference between my rhythm disturbances by my sudden symptoms alone and from the feeling I have in my chest.  I am over sensitive Liz to my arrhythmias (not always a good thing!!)  I try to comfirm the arrhythmia by feeling my pulse to see whether it is a "regularly" fast rhythm like Atrial Tachycardia  or "flutteringly regular", usually fast rhythm like Flutter or "irregularly" fast, but can be at normal or slow speeds, when in AF.  I usually am close to fainting with Ventricular Tachycardia so I know when a significant arrhythmia is happening.

Often one arrhythmia can mask another and this is very true for AF/Flutter,  but a pacemaker should detect anything new happening. When my pacemaker was first implanted, before hospital discharge, my EP found I was having episodes of Atrial Flutter, so this was very new to me. I hope you get some answers and relief for your symptoms


Probably not

by AgentX86 - 2019-11-25 12:30:43

If they're isolated PVCs,  most pacemakers won't trigger on them at all. You can use your remote monitor to capture an EKG and your PM tech and EP can see the difference.


by AgentX86 - 2019-11-25 12:37:17

It took a good EP to distinguish my flutter from Afib on  12-lead EKG. The ER cardiologist couldn't tell the difference, even though I could (my EP showed me what to look for). My flutter was unusual in that it as irregularly irregular, much like Afib.

Irregular Flutter

by Gemita - 2019-11-25 15:25:22

Hi AgentX86,

A few questions.  I was wondering how rare irregular flutter is or can this be a common finding ?  Would you say it is an extension of AF or a separate arrhythmia ??  Does it originate in the left or right atrium ?? I know regular Flutter is easier to stop with an ablation than AF but presumably "irregular Flutter" is more complicated ??  

AF and AFL

by AgentX86 - 2019-11-25 22:58:40

The to are more or less unrelated.  THey're related in that both are caused by errant electrical circuits in the heart but unrelated in how they work.

AF is caused by abnormal electrical connections in the heart causing chaotic muscle contractions.  Ablation and Maze procedures work on AF by burning/scarring the proper channels in the heart to block the asynchronous pathways.

AFL is a little different.  The sinus (SI) node starts a heartbeat, which is normally conducted across the right atrium (RA) to make the RA contract. It then spreads to the left atrium, and then through the atrio-ventricular (AV) node to the ventricles.  The purpose of the AV node is to slow this signal so the ventricle has time to fill before it contracts.  In "typical AFL", this signal continues around the right atrium and continues around to retrigger the SI node to trigger it to start another heartbeat (reentrant).  This time is very short so the atrial heart rate is very high (often 240 to 300bpm).  The AV node slows this down to protect the ventricles.  The AV node blocks one of two or two of three of these signals (a 2:1 or 3:1 block) to get a high, but sustainable heart rate of perhaps 120 (240/2 with a 2:1 block) or so.

The solution is then to break this circular path.  The flutter ablation puts an insulating scar across this path, which is usually (but not always) the pulminary vein (hence a pulinary vein isolation - PVI). This is almost always in one direction and fairly easy to spot on a 12-lead EKG by a sawtooh (always in one direction) waveform superimposed on lead III.

"Atypical atrial flutter" is anything that's not "typical atrial flutter". ;-)  It can be the errant signal going the other direction around the heart or as in my case, in the left atrium. It's identified by the sawtooth waveform with the teeth of the saw the opposite direction on lead III. Mine was caused by a failed Maze procedure to stop left atrial Afib.  The AF went away, sorta, but was immediately replaced by atypical flutter. Wasn't a happy camper!

The solution is the same but it's a lot more difficult because the ablation has to be done in the left atrium, which means that the septum between the atria has to be pierced to get the catheters from the RA into the LA.  The task is a lot more difficult.  I had three such failed ablations.

The reason mine was irregular had to do with my AV node.  It was slow, so while my LA was fluttering at 240-300bpm, I'd have three, four, or perhaps five atrial beats for every ventricular beat.  The heart rate was then about 80-100bpm but irregular as each beat would be a different ratio.  Whever the AV node and ventricals had reset, the next flutter signal would trigger them.  Then several would be dropped until the AV node allowed the ventricle to fire again. The reslting heart rate was the atrial rate - the AV maximum AV node rate.  In electrical engineering, we call this "heterodyning".  In music it's called a "beat frequency" (like tuning a piano).

To answer your direct questions, it's rather unusual. EPs are rather surprised by it.  My form is very rare because a Maze procedure itself isn't common (the chest has to be cracked to get at the heart, so it's "never" done without some other reason to be fiddling with the heart).  And one to fail in this manner is even more rare.

Flutter is almost always in the right atrium but I like to be different.  ;-) Most EPs will have seen it in the LA too. Cardiologists often can't tell the difference, though.  That's why you hire an EP. They're trained to identify unusual variations on the theme.  Few cardiologists can even identify slow (as in my case) flutter and think it's just a rather fast NSR. I knew when I went into flutter because my heart rate would go from 50bpm (awake) to 80-100bpm, before it broke into the irregular patterns. ER cardiologist always patted me on the head and sent me on my way.  My cardiologist could see it and sent me to an EP. That's why you have a good cardiologist on your side too.

In my case the irregular flutter is a variation on the theme caused by something unrelated to the flutter. The "normal" atypical flutter is just flutter going in the opposite direction, so the ablation is the same.  If it's in the LA, as I said above, the septum between the RA and LA has to be pierced to gain access to the LA so right there, it's a more complicated problem.

Thank you AgentX86

by Gemita - 2019-11-26 03:54:27

Wow what a response. I wasn't expecting that !!  This is a study for me and I am having to re-read again and again your post on AF and AFL to grasp it all.  How truly complex and amazing our bodies are when they work as they should but when something goes wrong the fix is not always straightforward is it.  I will private message you in a day or so if I may on this intriguing subject.

Just wanted to say on Liz's post that I too am somewhat unclear as to what the monitoring role of my pacemaker really is. I can understand its function for me personally but I am assuming that my pacemaker is also a monitor to pick up certain events that may need treatment or warrant further investigation. For example my pacemaker saw NSVT and this episode triggered a report which was commented on during a recent check. In the case of PVCs and/or AF, i understand if we generate a download during a period of symptoms they should be able to confirm what rhythm we were in at the time. However could we not ask our pacemaker technicians to programme our pacemakers to keep a log of all arrhythmias seen, including benign ectopics, to show dates, duration of episodes or something like this ?  I am assuming the pacemaker is able to be programmed to answer many questions. Would this drain battery ?? Thank you AgentX86


by MrTech - 2019-12-01 10:07:15

Hi all, 

AF is easy to detect and be recognised by the pacemaker (as long as the sensing is working correctly which is usually the case).  The AF  atrial signals is and even easier to recognise on 12 lead ECG. The atrial rate can be around 180-300 ms (very quick!). 

Single PVCs are simply one early ventricular beat being sensed by the pacemaker so its pretty easy to differentiate the two. While a PVC won’t be stored to view, there is normally a section in the stats where you you can how many PVC’s you get per hr. depending on make of Pacemaker. 

AF is usually triggered by ectopic arising from the pulmonary veins in the left atrium but can occur anywhere. The signals cause chaotic signals where the atrium doesn’t really pump properly and looks like a bag of worms (if you can imagine it). 

Typical Atrial Flutter is a when a stable circuit is set up that causes the signal to be stuck in a loop in the right atrium. When this happens it will suppress the sinus node.  

Both require completely different types of ablations to treat (If ablation is decided upon)

hope this helps. 


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