How fast is the left atrial fibrillation? - AF Association

AF Association

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How fast is the left atrial fibrillation?

Physalis
Physalis

Cleopatra's owner said "it seems that the medication I am taking will do nothing to prevent the atria from continuing to fibrillate at 500-600 bpm".

This came up in a recent post and I am now wondering if this figure varies from person to person. I was under the impression that because I had AFib with RVR (rapid ventricular response) my ventricles were keeping up with my atrial fibrillation up to 200 or more. Was I wrong in thinking that? Was my atrial fibrillation going at 500-600 bpm and, although my ventricles were doing their best, they weren't really keeping up at all?

46 Replies
BobD
BobDVolunteer

I think it impossible to define ANY rhythm if your atrium is fibrillating. For as long as I

have been involved with AFA ( since inception in 2007) it has been described as writhing like a bag of worms. The electrical interference is such as to make any measurement meaningless.

What signal gets through to the ventricle may well be influenced by but not controlled by that fibrillation. (sorry about the italics creeping in there._

Physalis
Physalis in reply to BobD

If you can't measure it, how can anyone say it's fibrillating at 400-600 bmp?

BobD
BobDVolunteer in reply to Physalis

Beats me. If there is no rhythm how can you count beats?

jeanjeannie50
jeanjeannie50 in reply to BobD

Bob, you accidentally hit control+I (that's I for India, not a one and that instructed your text to change to italics when you typed). If you wanted to and I'm sure you don't, you could edit your post, highlight the affected text and do control+I again and it would go back to normal text. If I type control+I you can see that my text turns to italics.

Jean

BobD
BobDVolunteer in reply to jeanjeannie50

I worked that out but was busy. thanks Jean

ectopic1
ectopic1 in reply to BobD

You're confusing frequency with regularity, irregular waveforms still have a frequency, it's just that the frequency isn't regular and constant.

When you're in AF, your ventricular rate isn't constant either, so by your argument the ventricular rate also wouldn't exist. During AF my VR varies from 180-260, and the reason we know it varies from 180-260 is because it's been measured at 180-260. You can calculate the rate by measuring the time interval between any pair if contractions, and since the rate keeps varying you will get a different answer depending on which pair of beats you use.

If you've ever listened to an FM radio, FM stands for frequency modulation: the audio that you're listening to has been used to vary (modulate) the frequency of the radio signal. You can hear the broadcast because the frequency varies, but the reason you can tune the radio is because you also know what that frequency is, otherwise you wouldn't be able to select one channel from another.

The first time I was in hospital with AF the cardiologist I saw told me my atria were ‘fibrillating at 400 BPM + but fortunately your ventricles can’t keep up, otherwise you’d be dead’ 😳 That stuck in my memory! Now and again I can feel a sort of vibration above the AF palpitations which I find very scary. I believe the AV node is what protects your ventricles as it can’t keep up with the impulses trying to pass through.

Physalis
Physalis in reply to Buffafly

How did he know that? I've often wondered why some people are asymptomatic and others suffer a great deal. Maybe it is because some hearts with AFib are fibrillating much faster than others, so much so that they are writhing like a bag of worms!

It could be that my ventricles were, in fact, keeping up with my atria.

CDreamer
CDreamer in reply to Physalis

It’s unlikely as AF is irregular and the rate will be filtered by AV node which will protect your ventricles. The highest HR I’ve seen for AF is around 220. As Bob said, in AF there is no rhythm - just chaos.

Now if you have Atrial Flutter which is a regular Arrythmia, then there is a formula 2:1 so if your atria beat at 300 then your HR will be 150 because only 50% of the electrical impulses get through the AV node.

AV= Atria/Ventricular node.

ectopic1
ectopic1 in reply to CDreamer

With flutter, there is a danger of 1:1 conduction, that's precisely why rate control drugs are recommended with flecainide. If you're unlucky, the flutter induced by the flecainide can be slow enough to pass through the AV node.

"Caution should specifically be exercised with the use of class 1 antiarrhythmic drugs in monotherapy in patients with AF. These drugs may prevent AF recurrences. They can, however, convert AF into slow atrial flutter, which may conduct one-to-one to the ventricles....leading to cardiogenic shock and even sudden death."

Heidbuchel et al: Recommendations for participation in leisure-time physical activity and competitive sports in patients with arrhythmias and potentially arrhythmogenic conditions

CDreamer
CDreamer in reply to ectopic1

Thank you for that clarification.

daysyday1
daysyday1 in reply to ectopic1

Ectopic1 I was interested in your post, especially the part in italics as I am on a class 1 antiarrhythmic drug as monotherapy. I have been reading a paper about it and there seem to be warnings about flecanide as monotherapy which can be fatal if given after a heart attack. My concern is that I have had AFib for 12 years, then 2 years ago I had a spontaneous coronary artery disection, (SCAD) which caused an MI. I'm quite concerned now.

ectopic1
ectopic1 in reply to daysyday1

If you're worried, it might be worth checking with your doctor, do you have a regular meds review?

There are two issues with flecainide that I know of, but I don't know whether they're related. One is the increased mortality for patients with a history of ischaemia, the other is the tendency to cause atrial flutter referred to above. The quote is from the recommendations relating to sports activity, the risk for patients who don't exercise may be lower. Do you get any flutter?

daysyday1
daysyday1 in reply to ectopic1

Thank you for a prompt reply ectopic1. I am fortunate to have no history of eschemia at my angiogram 2 years ago and as far as I know, I do not have atrial flutter. At my age and with all the arthritis, my activity is confined to walking. The doctors seem very lax with meds reviews and tend to leave it to the pharmacists. The EP did check my meds 14 months ago and nothing has changed since then. So your reply is assuring but when we are out of lockdown, I think I will make an appointment, or at least arrange a phone consultation to go through my meds for an update. T

Hank you for your help.

Buffafly
Buffafly in reply to Physalis

I assume that recordings can be made during electro physiological studies and that is how the impulses, even though chaotic and very fast, can be counted.

Physalis
Physalis in reply to Buffafly

We live and learn!

Singwell
Singwell in reply to Buffafly

I get that fluttering too - like a hummingbird trapped in my chest. Not every time luckily.

Buffafly
Buffafly in reply to Singwell

Brilliant description!

Singwell
Singwell in reply to Buffafly

One has these entertain oneself somehow during an episode. Mine are - person hammering my chest from inside, trapped hummingbird and an army of ants charging up and down my limbs (that's the BP going AWOL - I get tingling and pins and needles)

Buffafly
Buffafly in reply to Singwell

😂 Is it ok to laugh? I can imagine the ants - are they leafcutters or the evil red ones?

Singwell
Singwell in reply to Buffafly

It's completely fine. Where are we without it? Alas they're the red biters... Gillyanne

Completely confused by this post (although that could be useful too!). I use a Kardiamobile which tells me my BPM during an AF episode. When in A and E they've measured my BPM also on an ECG. Actually I've never been up to 200 but I know it's possible. Have I understood it right from responses here that 1. There's a difference between atrial flutter and atrial fibrillation (CDreamer) 2. Measures of BPM do not represent the fibrillation rate of the atrial chamber only roughly half that rate during an AF episode. Hence the discrepancy in numbers. BPM only an average anyway surely? Love to understand more please!

Buffafly
Buffafly in reply to Singwell

Yes, you’ve got it, more or less.

AF - Atria quiver randomly at 400 +, AV node passes some impulses through so ventricular BPM can vary from 200 BPM down to 60. Above 100 is AF with RVR (rapid ventricular response) and the more chaotic and fast the response is the worse you feel (the last bit is my observation only as some people can walk around OK with high rates while others are downed with 130 so I’m guessing other factors including fitness come into it and it’s not just speed that counts).

AFlutter - Atria beat very fast but regularly and the AV node blocks according to a formula so 1:2 might be 150 but 1:3 would be 100 and 1:4 75.

Atrial tachycardia with frequent ectopics can mimic AF.

And yes the BPM is an average which is why I record longer than 30 secs on Kardia and watch the numbers go up and down! I get angina during peaks 😖

Hope that helps 💜

Singwell
Singwell in reply to Buffafly

It does. And I'm sorry about the angina. Personally I'm not good over 100BPM unless I'm exerting - as in brisk walk uphill. So clearly it's that nonsense going on in the upper chamber that disturbs me. I'm fortunate that very rarely do I have pain.

Physalis
Physalis in reply to Buffafly

I think I can understand it a bit better now. So we all have AFib with CVR (controlled ventricular response) but some are more controlled than others!!

Why that is, is another question.

Mostly my AFib hr averaged about 140 but I remember recording it at over 200 and on another occasion, standing at a bus stop, I could feel my heart going fast, did an ECG - it was 195. Maybe I felt a little weak but by the time I got off the bus I was OK.

Buffafly
Buffafly in reply to Physalis

Well sort of, but in medical terms AF RVR is AF above 100 BPM and CVR is AF below 100 which can happen naturally or with medication.

Physalis
Physalis in reply to Buffafly

Yes, I can understand that. I hadn't realised that my AFib was being controlled but I can now see that it was.

ectopic1
ectopic1 in reply to Physalis

This shows how my HR varies between 140 and 235 in the space of a just a few seconds whilst in AF (in blue), compared with atrial flutter (in red), during which my HR is steady at 125.

i.imgur.com/AVtQXpe.png

ectopic1
ectopic1 in reply to Singwell

The rate your Kardia is measuring is the ventricular rate, not the atrial rate.

Singwell
Singwell in reply to ectopic1

Yup. I think I got it! 😉

I understood that atria "quivered" in A Fib rather than the atrial cells contracting properly in synchronisation.

I have a recording of 243 bpm in AF. I was running at the time. I was asymptomatic other than the high rate, and not even noticeably slower than normal. (I did stop running temporarily when I realised how high it was).But when I developed atrial flutter after my succesful afib ablation I was rate controlled at 140bpm, However I was gasping for breath just walking into the kitchen to make a brew!

I assumed that despite being in afib my atria MUST have been pumping fairly efficiently in the former (afib) case, but clearly not in the latter (flutter) case as I was starved of oxygen .

But in both situations my heart would also have been affected by the medications I was taking at the time. In the former I was on 120mg mod release verapamil rate control but probably with an extra 40mg normal release in addition (taken when I realised I was in afib). In the latter (flutter) case I was on Flecainide 50mg x 2 normal release rhythm control , plus 200mg diltiazem mod release rate control.

Or did the better ventricular rate control in the latter, prevent the ventricles speeding up and making up for the poor atrial pumping?? And consequently make me feel worse?? ( but probably a lot better for the health of my ventricles!)

Or is comparing flutter with AFIB like comparing apples and pears?

It's impossible (for me anyway) to understand!

To cap it all the flecainide was also probably to blame for the development of the flutter!

As BobD says often: mongrel condition!

Consequently i think the best thing is not to be in either Fib or flutter if it can be avoided .

Hence why I now think ablation is the best route ( but also conscious I may just have been lucky as I did not have any co morbidities to affect the outcome).

Ps . I was running at the 243 bpm as initially ,and for 20 months after AFib diagnosis, I found running put me back into NSR. Sadly after my 12 th (ish) AFib attack that stopped working and that's why I ended up on Flecainide.

Buffafly
Buffafly in reply to KMRobbo

What did you use to record the rate of 243?

You just won't accept it, will you.

You can fin it it Guyton & Hall, and for that matter, you can even find it in Wikipedia if you take the trouble to read it. If you're interested in what's going on with your heart, why don't you read about it instead of just assuming?

amazon.co.uk/Guyton-Hall-Te...

Physalis
Physalis in reply to ectopic1

I don't understand what you are trying to say. What am I assuming? I did assume that my ventricles were keeping up with my atria but I can now see this is not the case.

ectopic1
ectopic1 in reply to Physalis

You said " I was under the impression that because I had AFib with RVR (rapid ventricular response) my ventricles were keeping up with my atrial fibrillation"

From Wikipedia: "In AF, there is no regularity of this kind, except at the sources where the local activation rate can exceed 500 bpm."

Buffafly
Buffafly in reply to ectopic1

Don’t be rude, it is very complicated to follow and people like to try to work things out for themselves on their path to understanding 💜

Physalis
Physalis in reply to Buffafly

Yes, before I joined this group I thought everyone who had AFib was affected in the same way that I was. Now I've realised how complicated it all is.

So some people with CVR start off with RVR and it is controlled by medication. If I had been treated with Flecainide etc etc could I have quite happily ended up as a case of AFib with CVR?

Buffafly
Buffafly in reply to Physalis

Who knows? But usually Flecainide is for rhythm and other drugs such a bisoprolol and diltiazem are for rate and they are often prescribed together. If you were not prescribed Flecainide there was probably a good reason. I can’t have it.

Physalis
Physalis in reply to Buffafly

My doctor could only prescribe bisoprolol. I went straight from that on to ablation.

Singwell
Singwell in reply to Buffafly

Personally I found this a very helpful post and agree there is no need for rudeness. In fact + there could not be. Greater Assumption than the statement 'you just won't accept it'! It's by asking questions and making mistakes that we learn.

Physalis
Physalis in reply to ectopic1

I looked at the Wikipedia entry for AFib. One thing I did find interesting was that a quarter of people have paroxysmal, a quarter persistent and a half permanent.

en.wikipedia.org/wiki/Atria...

Garmin 305 running cycling watch with chest belt ,( electrical). Very confident about it's rate accuracy as was calibrated against NHS ECG on 3 occassions: firstly by paramedic @165 bpm , it's how i was diagnosed. I just had the high rate on the Garmin. I was going to go to work as I felt fine , but my wife rang 111 who sent an ambulance. I had actually put the Garmin in the bin as I thought it was broken. I told that to the paramedic who did the ECG, who said, "well you better get it out of the bin".The other two times where in A&E when I turned up in A&E at my local hospital . In high rate AFib. They always put a monitor on my finger which showed a rate of 50% of my Garmin. On both occasions I insisted on having an ECG (as I had seen the error in hospital on my first visit). Again on both occasions the Garmin figure was confirmed by the ECG( within reason, my HR jumped around when in afib anyway even when lying down).

Buffafly
Buffafly in reply to KMRobbo

Eeeeeek!

???why Eeeeek?

Buffafly
Buffafly in reply to KMRobbo

That is incredibly fast and I can’t believe you were still standing 😳

I was totally asymptomatic, no pain or shortness of breath or discomfort . Having said that when the running cardioversion trick stopped working I was in fast Afib 130 to 195 resting for 8 days until I was cardioverted by a flecainide infusion. I was tired after 8 days of it.

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