Clinic follow up - DDR or VVI?

Following on from my recent thread about settings, I have now had my out-patient visit and discussed in detail with the cardiologist my issues. I am in a cleft stick - either to leave my settings as they are (because changing them runs the risk of further  PMT) or revert to VVI to act of a backstop if my rate falls to below 40. On the current settings with sensed/paced AV delay of 225msec and similar Post Ventricular Atrial blanking I am mostly fine but on exercise this only allows tracking up to 120 which may not be enough for  strenuous effort. Sometimes I can exercise and remain  in my own native rythm and can achieve rates of 130+ when I am fine - but this is unpredicatble. I am told I go into Wenkebach or 2:1 block at higher rates. The message was to try to train to keep my rate below 100.

The alternative of going back to VVI is that on exercise if my rate doesn't respond I feel really light headed (worse than with the PM operating). On the other hand I am mostly in normal rythm so it obviates the risk of PM arrythmias but I am a bit concerned that if my block worsens I will only pace at a slow rate - my resting pulse anyway is slow - low 40s at night. The other finding that alarmed me was that I was told my I was pacing in the ventricles 33% of the time - which I find reallly surprising because (a) I wear a continuous ECG monitor a lot of the time and this only shows the PM operating with exercise and (b) I am generally very aware of the PM functioning. After all, 33% of the time is 8 hours per day and I doubt if I am recording more than 10 mins paced activity on a threee hour strip. Anyone know how these percentages are calculated? 

Anyway my decision has been to stay where I am in DDR for the moment and just hope things will improve with exercise training and once my anxiety levels stop red-lining! 

 

5 Comments

Settings adjustments while exercising..

by USMC-Pacer - 2024-06-07 08:57:47

I dunno if it is available to you, but when I was having lots of issues exercising, my EP/NP put me on a treadmill with all the monitors and fine tuned my AV Delays, which for me corrected my issues. 

If they can fine tune your device and raise your MTR, I think you would feel much better. 

From what I read here, I think you really need to campaign for yourself with some clinics as they just don't seem to want to do the work. Good luck..

 

Exercise and heart rate

by AgentX86 - 2024-06-07 13:26:45

The reason you're going into 2:1 conduction is that you're exceeding the "maximum tracking rate", which is the heart rate where the ventricles track the atria.  It falls back to 2:1 to keep the ventricles under the MTR, while keeping A/V synchrony. Your rate is set really low, for some reason, likely PMT. Mode switching from DDD to VVI might be the way to avoid PMT, not sure.  It's often used to supress atrial arrhythmias. Keeping your rate below 100 must suck.  I know what I feel like when mine can't get above 100 (odd things are happening). There isn't enough air in the world to fix the "short" in "short of breath".

I can understand VVI causeing problems but VVIR (R = rate response on) should fix that, after some amount of tuning. I'm not sure why why can't do DDD or DDDR, or maybe mode switch between DDDR and VVIR, when PMT is detected. Dunno, Your doctors know more than I do.  I'd ask more questions, not to interfere, but to learn.

The pacemaker measures the pacing percentage. It knows when it's pacing and when it's not.  That mumber couldn't be more reliable.

 

 

Replies

by Xtrabeat - 2024-06-08 07:29:47

Thanks very much for the comments.

 USMC-Pacer I think that is an excellent suggestion but I am not sure I am going to be able to persuade anyone to do this here. I will follow up.

AgentX86 there is so much about PM settings that I don't understand but clearly changing one has an effect on many others! For example, my tracking rate is set because of the amount of atrial blanking. This is set at 225msec and the problem (I think) is that I get retrograde conduction with inverted p waves occuring after the QRS which would in turn initiate a pacing beat and this was felt to be the mechanism of PMT. Despite this I still get short episodes of PMT (8sec or so) which apparently the PM aborts. The post ventricular AV delay also 225msec I assume for the same purpose.

The slow rate at 40 because my "normal" heat rate at night is always in the 40s and if set higher (say 60) I would pace most most of the time at rest. 

I am very surprised that the V pace percentage is so high. I have just run a couple of tapes - one during exercise whee the PM was operating for about 5 min in 90 min total exercise time and then a recording in the evening doing light work and then watching TV where I can see no pacing beats in over 7 hours continuous recording. 

I am still very much on a learnig curve but each time I go for a check, I am not sure what to ask ! I also feel that they are probably getting a bit fed up with me - I have had a total of 6 visits in the last 6 months.

I really appreciat the help - for now I am trying to see if I can get fitter and manage my problem day to day. While not doing much I am OK - and that includes a lot of moderate activity ijn the garden etc.

Pacing settings VVI R

by Selwyn - 2024-06-08 14:04:42

Why not try VVIR?  ( The VVIR mode is a single chamber ventricular pacing mode with rate response enabled. This means that the pacing rate is dependent on your. activity  as detected by a venticular sensor.. ) Have a decent upper rate limit so if necessary you can exercise  eg. to 130 bpm. VVI should ignosre your atrial activity eg. your inverted extra P waves and stop your pacemaker mediated tachycardias. Just an idea!

It seems crazy to try to limit your upper rate to 100 bpm. if you are active.

The pacemaker readout is totally reliable. Your ECG sensor may not have that reliability - I have yet to hear of a body worn ECG device with  100% reliability when it comes to pacing. A number of these devices are not approved for use with pacemakers for that reason.

VV!-R

by Xtrabeat - 2024-06-12 06:41:08

Thanks Selwyn I will ask about VVIR.

Regards the monitoring, it is very evident when I pace because the QRS morphology is completely different. During normal activities I am in sinus rythmn (with a few ectopics!) so it would be easy to seee if the pacemaker were working - which it doesn't appear to be. I am going back to have this checked in a month or so.  

 

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Member Quotes

The pacer systems are really very reliable. The main problem is the incompetent programming of them. If yours is working well for you, get on with life and enjoy it. You probably are more at risk of problems with a valve job than the pacer.