Atrial High Rate Episodes

Atrial High Rate Episodes

by Gemita - 2022-12-17 14:27:10

Penguin, Our doctors set up our pacemakers to record/store the information they want to see based on your health condition/symptoms.  In your case it seems your Atrial High Rate is triggered when your heart rate reaches 150 bpm and above.  Mine is triggered when it reaches 171 bpm and above for a certain duration to avoid triggering a response too often with my frequent in and out arrhythmias.  This is not to say that your pacemaker will ignore slower, longer episodes of AF.  It just means that they will not be recorded/stored on your pacemaker’s electrogram until they reach 150 bpm or above, but lower rate episodes should still be recorded in the AF log history as part of your % burden in AF, particularly if your episodes increase in duration and frequency.

They are usually not too concerned about AF if the heart rate can be controlled and you are anticoagulated if you have risk factors for an AF stroke, but AF can be difficult to tolerate even at a slow rate.

My doctor places all my atrial tachy arrhythmias under the same umbrella, since one may set off another.  For example I have Atrial Fibrillation (irregular arrhythmia) which can develop into Multi Focal Atrial Tachycardia (also an irregular arrhythmia) and sometimes into Atrial Flutter (mainly regular arrhythmia) and then to Supraventricular Tachycardia (regular arrhythmia).  All these arrhythmias have been documented by a Reveal Linq implanted monitor.

As I have said, Atrial Fibrillation is not usually a dangerous arrhythmia if we can control the heart rate and protect the patient from a stroke if they have risk factors, but it certainly needs controlling otherwise it can become persistent very quickly and we may become symptomatic and this could lead to heart failure symptoms in the longer term.

There is nothing better than a surface (external) 12 lead ECG to confirm a rhythm disturbance.  Although the pacemaker electrogram is adequate, it is always best to follow up with a surface ECG to confirm any arrhythmia present if there is any doubt.  Of course intermittent arrhythmia symptoms may be missed with a brief external ECG, so you may need longer term monitoring to better capture what is going on. External longer term holter monitoring may be useful in this case.

The pacemaker will certainly give your doctors lots of useful information about your rhythm disturbances, but it cannot store on an electrogram every arrhythmia since it would run out of space which needs to be kept for important housekeeping/pacing tasks and storing/recording important data, like a very high heart rate event in the atria or ventricles.  Any slower, benign ectopic beats for example, may be rejected.  Mine certainly are.  I hope I have answered your questions.  

Please speak to your doctors about your difficult symptoms at night.  They need to know how symptomatic you have become.  I hope you feel better soon.

Have you deleted your response in error?

by Gemita - 2022-12-18 12:51:05

Hello Penguin, 

I see your response to my comments above have been deleted?  Nonetheless, I will still post this.  Thank you for your kind words.  When my arrhythmias first started I was extremely frightened because I couldn’t grasp what was happening.  

Since my AF diagnosis in 2014 I have developed strategies to manage my symptoms better and with this knowledge comes reassurance that I am in control, not my arrhythmias.  They can still cause awful symptoms but I rarely need emergency support now.  I no longer take anti arrhythmic meds because they became pro arrhythmic.  I am now much better with only pacemaker support keeping my heart rate at a steady 70 bpm since I had predominantly bradycardia induced arrhythmias.   A few years ago I was offered an ablation but was told I would need at least two procedures.  I chose the pacemaker route because of bradycardia and syncope and I have not been disappointed although I may need to re-visit an ablation in the future should my symptoms and arrhythmias worsen.

Penguin you certainly know a great deal about your pacemaker and settings and I am very impressed.  I didn’t mention Mode Switch but I see that you know all about this.  My upper rate setting is 130 bpm also, but my Mode Switch is triggered at 171 bpm ?Medtronic factory setting?  I have AF with a rapid ventricular response rate which can go well above 200 bpm when it starts.  My ventricle high heart rate trigger is set at 150 bpm. 

Penguin in my experience doctors cannot say too much until they have studied your arrhythmias.  Electrical disturbances are so variable.  I had an electrophysiology study done, when fortunately I was in AF at the time, so they could see exactly from where my arrhythmias originated and whether I had any extra pathways.  Even so, my technicians still have difficulty knowing what arrhythmia I am in sometimes from my pacemaker stored ECGs and have to send my pacemaker reports to the Medtronic rep for analysis.  The rep always suggests an external ECG because of potential signal sensitivities coming from my pacemaker leads (owing to any slack with the tip/tissue interface).  My technicians diagnosed initially 1:1 SVT which became Multi focal AT on closer inspection.

Yes unfortunately one arrhythmia can set off another or after successful treatment for one arrhythmia, another arrhythmia may surface or be “unmasked”.  This can often happen after a successful ablation for Atrial Fibrillation when Atrial Flutter may develop.  

Have your doctors actually diagnosed PMT and how did they confirm this?  It sounds to me as though there are many questions to be answered particularly from your night time symptoms.  All I can say as an experienced arrhythmia patient, is that symptoms can vary and cause instability when blood flow is affected and not circulating well during an irregularly irregular arrhythmia like AF.  I am not at all surprised that you are feeling so poorly and even at low heart rates AF can still cause many difficult symptoms.

There are several members here with Kardia Mobile 6 lead and although Kardia has not been tested for use with pacemakers, they still work and if you send any symptomatic episodes in to your clinic, or take them in with you when you next attend clinic, they can usually give an indication of the arrhythmia you are/were in.  Of course, I would send in a transmission from your monitor first and keep doing this until they start to listen to you.

You are certainly not whinging.  You are being very brave and you just want some answers and better treatment to steady your arrhythmias. Please feel free to message me any time.  You don't have to suffer in silence.  Take care

Sorry about the deletion

by Penguin - 2022-12-18 15:13:15

Hi Gemita, 

Sorry about the post deletion. I tried to edit one sentence and the lot disappeared!   Wasn't expecting that! 

Re: PMT - I reported some mild symptoms a while ago and when the clinic investigated a brief PMT showed up which was around the right date / time.  I discussed it with the clinic.  They confirmed that PMT can be caused by undetected AT.  

I looked into my AT detection rate and it looked too high at 180 bpm because I knew that my h/rate rarely rises above 140 -150 bpm. I then found this which describes how Abbott devices should behave when they detect AT.  

‘The Auto Mode Switch algorithm (AMS) switches the mode from DDD(R) to a ventricular-timing mode (DDI, DDIR, DDT, DDTR, VVT, VVTR, VVI, or VVIR) when the atrial rate surpasses the Atrial Tachycardia Detection Rate (ATDR) setting. At mode-switch, the device paces in the ventricle at the AMS Base Rate setting’ ....…….‘The ATDR parameter is always available because it is also used to classify events in atrial tachycardia and trigger ECG storage’. Re: Paragraph St Jude / Abbott Devices https://cdn.intechopen.com/pdfs/13772/InTechDifferent_automatic_mode_switching_in_dddr_pacemakers.pdf 

If you look at the statement in bold and consider what happens if the device fails to detect AT because the ATDR is set too high, it's logical that the device will a) fail to mode switch and b)  fail to trigger ECG storage and c) fail to classify AT events in the device's event recorder. ....hence no evidence for AT / A.Fib. for events which fall below the ATDR.

I ran my reasoning by the Abbott Rep for my area and it became clear that this is why there is no ECG or statistical evidence for my atrial arrhythmia which must occur below 150 bpm.

It was then disclosed that the ATDR has to be set at least 20 bpm above the patient's max tracking rate .   As mine is 130 bpm it became clear that the lowest ATDR programmable in my case is 150 bpm.   As my heart rates rarely reach 150 bpm, this ATDR will never record my arrhythmia. 

I'm tired out with it all. 

Hope this helps and I will look at your PM later too

by Gemita - 2022-12-18 16:46:34

Firstly when your post disappears again, try hitting the “backspace” it may just  re-appear.  We sometimes get a “Whoops message” when posting a response to a member or to a message that has been deleted or we have “timed out” or something like this, and if I backspace I can usually recover my message, copy and paste it to another application and then log out and log in again to the Pacemaker Club and re-post.  

Yes automatic mode switch for my Medtronic behaves in the same way.  The mode switch parameters are set by our cardiologist/EP depending on our condition being treated.  The trigger for mode switch is always set high (between 165 bpm and 200 bpm) and automatically occurs after detection of a fast atrial tachy arrhythmia of at least 15 beats duration I believe.  If both set parameters are not reached, mode switch will not trigger a mode change or store a recording on the pacemaker’s electrogram.  However, as far as I am aware, a heart rate over 100 bpm (which is classified as tachycardia) if it is prolonged and caused by AF or AT or any other atrial tachy arrhythmia, is recorded in my AF/AT history log or included in the % time I am in AF.  You should talk to your doctors and ask what they have set up to capture your atrial tachy arrhythmia episodes over 100 bpm for prolonged periods (say minutes to hours)?  Ask whether all prolonged tachycardia episodes are included in your % time in AF/AT and see what they say.  

But I go back to my earlier comments, the purpose of the pacemaker is not to serve as a heart monitor which I know is very frustrating when it could be a perfectly good heart monitor.  The purpose of the pacemaker is to pace and to provide certain anti tachycardia pacing functions to protect us during a “dangerously” high heart rate “event”.  Medication and an ablation is used to control a fast heart rate.  It is not the purpose of the pacemaker to do this, unless we have an ICD for a life threatening ventricular arrhythmia and atrial arrhythmias are not regarded as life threatening.  Only when our heart rates reach high levels the mode switch will occur so that the ventricles will not be pushed too hard or track the fast heart rates in the atria.  When certain conditions have been met, the mode switch switches back to tracking in the atria again.

What is to be done?  Clearly you are not happy.  You want better monitoring.  You could ask for longer periods of Zio patch or holter monitoring, or respectfully ask your EP whether your settings could be adjusted for a short period to pick up your disturbances say over a 3 month period, but of course mode switch would activate more frequently at lower rates, will use more power and you might therefore become more symptomatic than if your EP were to start you on a low dose medication to see if this might help calm everything down.  What you mustn’t do is to get upset or disappointed.  A lot can be done to help you but long term monitoring, in whatever form, is a priority for you in my opinion to fully understand what is going on.

I am in touch with my pacemaker technicians and ask them technical questions about my settings.  I suggest you do this too and ask what other features your pacemaker has to help control your arrhythmias.  There are many settings that can help smooth out arrhythmias and make you feel more comfortable.  I will send you some information in a private message tomorrow since it is supper time and hubby is waiting for his soup!   If you are very symptomatic at any time, you should seek help either from emergency services or by contacting your clinic so that they are aware of your difficulties.  Unless they know, they won’t do anything.  You have to keep pushing until you feel more comfortable.  Only you will know what you can and cannot tolerate.  I promise you it usually gets better and you will sleep well again