Hello all, what is everyone's experience of SVTs and how a Boston Scientific responds to same?

thank you



SVT (supraventricular tachycardia)

by Gemita - 2021-01-09 05:09:31

Hello Lisa,

I have a Medtronic so cannot speak on the effectiveness of Boston Scientific handling SVT episodes.  

I think it is important to remember though that a pacemaker is not a treatment or a cure for a fast arrhythmia like SVT.  Only medication to control heart rate and/or other treatments like an ablation, can ever really hope to treat or cure the condition.  A  pacemaker cannot stop a high heart rate, it can only prevent our heart rates from falling below the set minimum rate.

I have suffered from SVT and other arrhythmias for years, but fortunately my episodes are still only intermittent and usually stop on their own, although sometimes I have had to go to A&E/ER for help.  I am only taking low dose Bisoprolol now to hold down my high heart rates which in the past were seen by my Reveal Linq Implant to reach a maximum Ventricular rate of 300 bpm before crashing to below 30 bpm within seconds which I clearly felt, so pretty scary stuff.  I can still get breathless, dizzy, weak and get some chest pain but fainting spells with my pacemaker have largely been eradicated (at least when tachycardia is the cause) mainly because my heart rate is being well controlled with Bisoprolol.  Also thanks to a Mode Switching pacemaker feature, when my pacemaker detects a fast atrial tachyarrhythmia like SVT, AFib, Flutter, it switches from the programmed atrial tracking mode to a non-atrial tracking mode so my ventricular rate can be better controlled and less likely to cause symptoms.  It switches back to my normal mode when the tachyarrhythmia ceases.  

Although my Medtronic pacemaker is unable to stop my SVT (and other arrhythmias from occurring), I have found that a higher heart rate provided by my lovely device (70 bpm day and night) helps stabilise my heart rhythm, often controlling pausing, skipping, slowing, racing, fibrillating, fluttering.  For me having a pacemaker has really helped a lot to ease my symptoms and I would go further and say, it has helped to suppress my rhythm disturbances (although clearly this does not happen for everyone).  There are also several pacemaker features that can be used and set to suit each one of us individually to help control our symptoms.  I am still finding out about what is set up in my Medtronic pacemaker, but please speak to your doctors and ask if your pacemaker could be better adjusted to help.

What about you Lisa?  What sort of symptoms are you getting with your SVT?  



by AgentX86 - 2021-01-09 12:52:08

It may help but it's not the usual case.  According to my EP, it's unusual enough that he didn't even want to try.  Note that SVT really is a catch-all for a number of atrial tachycardias (SV == Supra Ventricular = above the ventricals) so one size doesn't fit all.  If your EP thinks you're a candidate, he may try.  In many pacemakers these modes are all built into the software and just have to be enabled.  I don't know about yours - you didn't state the model and I wouldn't know about a specific model anyway (you can look these things up online but would need to know what to look for). 

The easiest  way to find out is to ask your EP. He may even want to discuss it with you and choose a PM based on the discussion.  Always talk to your EP about these things.  Two-way comminications with your EP is critical in any case.

Depends a lot on each individual

by crustyg - 2021-01-09 15:49:47

Hi Lisa: as Agent says SVT is a catch-all for some different conditions (my EP doc and I had a long chat about whether classical cavo-tricuspid isthmus AFlut is actually classified as an SVT - IIRC he says not, I argue that it should be).

The only way that a PM can make a useful contribution to the management of an SVT episode is by overpacing the AV-node into a refractory state, so that it doesn't conduct all of the electrical impulses that reach it from the RA, and so slows down the rate of activation of the ventricles.  Artificial heart block - usually 2:1.  But this only works if the AV-node's refractory period is usefully long - too fast recovery and it may not be possible to overpace the RA to achieve this AV-partial HB.

Quite a few PMs can be programmed to try and achieve this over-pacing when they detect a sustained A-then-V activation which is clearly A-driven (all PMs can tell where the impulses are coming from by watching the timing and how it changes over time. Usually).  All PMs are designed to avoid PM-driven tachy (caused by retrograde conduction in AV-node from V=>A).

To really understand the pros and cons of trying to use your PM in an attempt to control SVT episodes would need more than you've provided - and, I suspect, more detailed information than the manufacturer provides in the standard EP-doc level BradyRef manual.  There's a lot of information about the detailed inner workings of PMs that isn't covered by the externally available manuals.  The good reps should know a lot more in this area.  I've certainly learnt a lot about MV on my PM from the manufacturer that isn't covered in the standard manuals, so I would expect the same to be true of the PM's ability to help control SVT by overpacing.

SVT query

by Lisarose - 2021-01-12 00:31:02

Thank you Gemita, AgentX86 and custyg for your replies, that is a lot of good information, will sort through all of it ☺️
Gemit? You indeeed about my experience? Basically in the early days of investigation, sudden tachy flutter sensation several times a day, seems to initiate in atrial only then my pacemaker detects this and triggers ventrical to speed up to match atrial, results in usually aprox 150bpm "dualing banjos" for any where from seconds to several minutes. My pacemaker tech says this pacemaker feature could be turned off to avoid increased discomfort, by wondering are though, it wouldn't stop the atrium from SVTs, to would only stop my ventrical from trying to catch up, my GP is chatting with cardiologist with an appt with same in near future.

In my experience...

by asully - 2021-01-13 23:26:42

The pacmaker mediated weinkebach is not fun (the 2:1) rate it will send you into when your atria goes above your upper limit.  I personally find it more unpleasant than my actual SVT runs.  It causes dysynchronization and messes with your cardiac output.  I am hoping to have them raise the rate at which my device mode switches to weinkebach so it is triggered less often.

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