Why 80 and why pauses?

This is my first post. I am 68.
I had a biventricular pacemaker (CRT-P) implanted last month because of persistent a-fibs. I would not risk a conventional ablation because I have two mechanical valves that could be compromised in the ablation process. So, I had a complete ablation of my AV node and now have no conductivity from that node. I am totally dependent on the device. Fine. No more symptoms and I feel great.
Just two question. How does the PM decide to keep me at 80? And why? My rate is set at 50-110. And, half the time I have “compensatory” pause between beats, i.e., 1,2,3,….1,2….1,2….1,2,3…. --although my rate is still eighty. Why the pause or the fast beats that had to be compensated with the pause?

5 Comments

PVCs?

by golden_snitch - 2011-08-18 02:08:04

Hi!

When you say they are "compensatory" pauses, you have given the answer yourself: you are having premature ventricular contractions (PVCs), only those come along with these kind of pauses. Now, the pacer can't do anything about PVCs. Sometimes you get them when you have a lack of magnesium and/or potassium, so supplements could help, but you would have to ask your doctor before you start taking them since too much magnesium or potassium can also cause problems.

The heart rate of 80 is "inspired" by the sinus node as Heidi explained. When you have had a complete AV-node ablation, the ventricular pacing lead will follow the rhythm the sinus node is firing at - unless you reach the max. tracking rate. So, it's not really the pacer that decides to give you 80, but the sinus node. If that bothers you, the only thing one could do is try to slow the sinus node down with betablockers etc. It's something that can't be re-programmed.

Best wishes
Inga

Pause

by Heidiglassmeyer - 2011-08-18 02:08:26

I also had my AV node ablated last year. I'm not sure how to answer your question completely but I can share my experience and what my EP told me...

Basically he explained that since my SA node functioned normally the PM could only pace to the upper limit (setting) So, if I exceeded the upper limit the PM would respond by "skipping" a beat (AV node) to keep up with my hearts natural PM. I am not sure if that is what you are describing. I have to say it's not the best feeling in the world if it continues for any period of time.

I am sure others with far more technical knowledge will respond as well :)

K, just re-read your post and I think you are saying this occurs when you are at 80 bpm? If so, my comments aren't very useful, sorry!

Take care,
Heidi

Depends

by ElectricFrank - 2011-08-18 03:08:04

After the AV ablation the pacemaker provides pacing of the ventricles. The question is how the pacer is programmed. If it is using the atrial contractions to determine the timing of the ventricular pace, and there is afib happening then the pacemaker would skip beats to keep the ventricle rate within limits. At times when there is no afib and it is below the upper limit you would have a normal HR response.

Another way to program the pacer is to ignore the atrial rate entirely and use Rate Response to determine the ventricle pace. In this case there should be no need for skipped beats as the RR can be set to stay below limits.

The pacer may have a feature that detects afib and switches between the two modes above.

As long as the current setup is comfortable it should be fine. If not there are options that make different compromises.

Hope this makes sense. It is hard to describe without diagrams.

Welcome to the club. I'm 81 and pacing away. I have an AV block without the need for an ablation. Also no afib so I have my settings at 50-150bpm. I hike, drive a Jeep in the back country and have enjoyed myself at 13,000 ft.

frank

Frank is right

by golden_snitch - 2011-08-18 05:08:49

Frank is right, I forgot about the Afib you have. But still in periods when you don't have Afib, the sinus node will determine the heart rate. When you have Afib, the pacer ignores the atrial rate (mode switch) and simply paces the ventricles at the programmed rates; as Frank said it determines the appropriate rate with the help of the pacer's rate response sensor. In that case there should be no skips or pauses. So, I'd still think you might have PVCs causing the pauses.
Best wishes
Inga

Between us we got it right!

by ElectricFrank - 2011-08-19 01:08:37

The great thing about this site is the wealth of shared knowledge.

frank

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