Annual review - positive experience

Upper rate limit

by Selwyn - 2024-07-19 14:04:48

I believe you have to shorten the A-V blanking to up the max. upper rate, though there is some risk of loop feedback if this is not done with due diligence.

I agree about the NHS. I can e-mail my electrophysiologist and they see me usually within the week, depending on how busy they are. 

It is a very British thing to grumble about public services. I attended the cardiology out patients this week at Liverpool Heart and Chest Hospital. I had barely sat down when I was invited in for an ECG. The tech. kindly showed me the result without me asking ( I had seen him a couple of months ago) and just had time to drink a cup of coffee before being called to see the doctor for a sensible discussion. 

Great service. Listened to and treated with respect.  

My nearest and dearest also receiving excellent service from the NHS ( waiting a couple of weeks before liver surgery for a colonic cancer metastasis).  Thank you for sharing your experience.

Upper Rate Behaviour

by Gemita - 2024-07-19 16:23:02

Hello Repero, thank you for your post.  I recently updated our FAQs on this very subject and have copied the relevant section below in case it is of help.  It is complicated and many of us complain of this device related arrhythmia, known as Wenckebach or 2:1 Block.

Yes I believe there are various ways to address this problem since there is never one setting but several different settings to try, that often work “together”. Of course I would hope that your clinic would offer you some exercise testing to try out any changes first, so that they can be adjusted while you exercise.  My AV Delay is set at 150 ms (sensed) and 180 ms (paced).  

Upper Rate Behaviour is a feature of dual-chamber pacemakers with atrial tracking mode. Upper rate behaviour occurs when the atrial rate increases and approaches the Maximum Tracking Rate (MTR). In dual-chambered pacemakers, it is necessary to limit the atrial rate at which the device can pace the ventricle.  This limit is called the MTR, and it is a programmable value. (The MTR interval has also been referred to as “upper rate limit” and “ventricular tracking limit”).   

The upper-rate behaviour depends upon the MTR and total atrial refractory period (TARP). The TARP is equal to the atrioventricular (AV) delay + PVARP (Post Ventricular Atrial Refractory Period). When the atrial rate exceeds the MTR, it results in pacemaker Wenckebach. If the atrial rate keeps increasing and exceeds the TARP, it will result in pacemaker 2:1 AV block.  

If properly programmed, the device tracks in a 1:1 fashion until reaching the programmed upper rate. As the atrial rate increases, ventricular pacing cannot violate the upper rate limit, resulting in progressively longer AV intervals. This is referred to as pacemaker Wenckebach. However, if the TARP is excessively long, abrupt 2:1 block may develop with a sudden slowing of the ventricular rate, which may cause symptoms. This occurs because when the atrial rate hits the TARP, every other event falls in the PVARP and is not tracked. Effectively, the ventricular pacing rate is one-half of the MTR. Undesirable upper rate behaviour is avoided by meticulous attention to intervals, by programming to allow a Wenckebach interval between the maximum tracking rate and the 2:1 block rate, and by allowing rate-adaptive shortening of the AV and PVARP intervals. 

Thanks

by Repero - 2024-07-19 18:20:30

Thank you both for your responses.

Gemita, I should have gone straight to your FAQ article, sorry. I have read similar online, but still struggle to fully grasp the details of how all these variables combine to give the desired result. I have downloaded an article with annotated ECG traces explaining Wenckebach which I am currently studying. I used to be a scientist. I am slightly alarmed that I am having so much trouble understanding this.

I have submitted an application to my health trust to obtain my pacemaker check report from today. Hopefully there will be some details in there to help me put it all together. It's not easy!

Clinics

by piglet22 - 2024-07-19 19:19:43

My UK trust closed the physical clinics nearly 4 years ago.

Not a happy bunny.

Now we get virtual device clinics, posh name for upload on monitor and a phone call back.

Then they stopped the phone call as well.

Yes, it's all to do with money and nothing to do with patient-cliniican interaction. You can go for years with not even speaking to someone for 10 to 15 minutes a year.

What does it achieve? Unhappy patients and probably unhappy staff.

After kicking off, I managed to get the phone call back and now my next appointment is face to face.

They messed up the last replacement so had better get the next one right.

These exercises achieve nothing, save nothing in the long term and spoil the healthcare patient relationship.

LIghtbulb moment

by Repero - 2024-07-19 20:08:49

Selwyn, Gemita: I think I now understand that the MTR, or Upper Tracking Rate, is in fact a programable item. Mine has been set at 150bpm (up from 130). This has meant that the Total Atrial Refractory Period (= AV delay + PVARP) has had to be reduced to be less than 400ms (the period between pulses at 150bpm). They did this by reducing my AV delay from 200 to 170ms. Assuming PVARP is at the default value of 225ms, this gives TARP = 170 + 225 = 395ms.

You probably didn't want to know any of this!

Piglet22

by Repero - 2024-07-19 20:15:55

Yes, it's depressing how decisions are just money based, losing sight all together of what the service was there for.

I already have just virtual annual reviews, but here they are now talking about closing the Pacing Clinic down and making the EPs redundant. Saves a few quid, but where do I go then to resolve my PM problems?

Light Bulb moments

by Gemita - 2024-07-20 02:15:08

They are a breakthrough, aren’t they!  Whatever our backgrounds, cardiac electrophysiology is challenging for all of us.  We are a challenge for our EP’s, so why not a challenge for ourselves?   The training required to become an electrophysiologist is lengthy, so why shouldn’t we expect to struggle trying to understand our own complex heart rhythms, not to mention the abnormal heart rhythms that can be pacemaker induced!  

It is a massive area and we can only hope to scratch the surface of understanding, given the complexity of some of our electrical disturbances.  We will never learn everything there is to learn about electrophysiology, since it is constantly evolving, so arriving at light bulb moments along the way, shows utter determination and a will to challenge this vast subject.  Thank you for your excellent calculations Repero.  Of course I want to know about this bread and butter stuff.

As far as pacemaker clinic appointments go, I have been extremely lucky it seems with my experience so far at a main London hospital.  I am still getting F2F appointments 6-monthly although I am occasionally required too, to transmit data to my clinic.  I am also able to email my technicians at any time for feedback on any difficult symptoms I might experience.  They will also readily answer any questions I might have about pacing in general and I find getting written confirmation like this invaluable.  

Repero

by Penguin - 2024-07-22 03:49:31

Thank you for the additional info. Valiant (member) may appreciate it. (See his most recent post) on the same topic and located in the S.West of England like you.  USMC Pacer has also posted about a lower MTR in combination with longer AV delays as the cause of his exercise intolerance.  Your post is very helpful. 

I have a question to tag on to this if you don't mind.  My Abbott Assurity device has AV delays which are flexible and vary according to need.  Any idea how the equations that you flag up, function alongside flexi AV delays?  e.g. mine work via an algorithm which shortens / lengthens them. Any scientific insight would be appreciated.

Many thanks