First Transmission continued...

Capture

by AgentX86 - 2020-10-11 16:38:45

Capture just means that the muscle is responding to the electrical signal given. There is a margin programmed in to cover changes. All they want to do is increase that margin by increasing the voltage. It's unlikely that there is a problem with the leads, just that your heart isn't responding as they originally expected or perhaps the lead is placed suboptimal. You'll be fine. Don't borrow problems.

Capture

by Sisterwash65 - 2020-10-11 17:57:08

So the PM is still “ working “ just not as programmed, or on a suboptimal level ? . I sure don’t want to borrow problems but I don’t like surprises either!

No doctor had ever mentioned pacemaker to me before the day I was told I needed one. I was just wondering about my lack of symptoms and your explanation helps. These PM’s are so complex I don’t know how any one person can retain all the knowledge necessary. It is truly mind boggling.

Thanks again, AgentX86

Pacemaker capture

by Gemita - 2020-10-11 18:55:08

Hello Sisterwash,

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192127/

I would suggest that we are so complex not our pacemakers.  Our pacemakers can be adjusted to suit our needs, but our individual health conditions that we have to live with may not be so easily managed.

I am sure you have seen the above link which is so helpful in summarising the sheer number of possibilities that could cause pacemaker capture failure.  It even mentions non cardiac causes for loss of capture from electrolyte changes to common medication.  For example, anti arrhythmic med Flecainide even after just one dose may (rarely) affect the capture threshold by up to 200%.  

When you go for your consultation I am sure they will check more than just your pacemaker, especially if no problems are immediately identified with your settings or improved after any adjustments.  Knowing the sheer number of possible causes will help you to ask what other tests might be beneficial.  

BUT it may be that just a simple setting adjustment as suggested by AgentX86 is all that is needed to improve capture and we are getting ahead of ourselves unnecessarily.  I am just the same when a possible diagnosis is initially given.  I usually research before anything is confirmed and attend my appointment with often fixed ideas of what is going on.  I then come away feeling somewhat perplexed when the outcome doesn’t quite match my assumed diagnosis.  However no one can say you won’t be prepared for your consultation Sisterwash.  I would rather have too much information than too little.

To summarise, "possible" pacemaker capture failure causes include:

1 Non cardiac causes like electrolyte imbalances, medication

2 Cardiac causes like fibrosis, cardiomyopathy

3 Lead dislodgement, fracture, premature failure, programming errors

You would probably be highly symptomatic if you had a major problem right now and you clearly do not have any significant symptoms at present to suggest this.  I cannot explain why you are not symptomatic but surely this has to be a good sign Sisterwash?

Capture

by AgentX86 - 2020-10-11 18:56:46

Sure, your pacemaker is still working (or they'd be getting you in faster) but perhaps with less margin than they'd like.  The margin protects against interference and changes in the heart itself.

A lot of us have been surprised when first told they needed a pacemaker.  I'm not in that group but I understand it.  I knew months before that it was an option for me.  But suddenly it wasn't.  It happens.  They probably didn't know it was in your future either, until it was. That's the way these things go but it could be a lot worse. 

My brother had a series of heart attacks and strokes about fifteen years ago and has had an ICD for most of that.  If anyone bumps him on his left side, down he goes and then gets zapped to bring him back.  Completely ruins his day. <no smiley>

Yes, these things are complex.  That's why they have factory specialists who are paid to know everything about them.  Many hospitals hire out their PM techs to the manufacturers, rather than have their own employees try to keep up with them.  That's often why they only use one brand of PM.  The service department is only trained on one OEM.

Good info, Gemita!

by LondonAndy - 2020-10-11 19:04:14

I have had my pacemaker for 6 years now and must admit that I never thought medication might affect it's performance!  It's good to keep an eye on this site, and learn from others - thank you.

First transmission continued

by Sisterwash65 - 2020-10-11 21:22:16

Great example why I love this forum !! It’s so reassuring to hear from knowledgeable people.

Just to be clear, I blame no one but myself for my shock at being told I needed a pacemaker. I knew I had Left Bundle Branch Block Since 2012. I researched it then and it was clearly stated there that a PM could be in my future. And I don’t expect a doctor to sit there and tell you what all” could “ happen !

Gemita, I read the link you included. Although I’ve read many I hadn’t read that one. Very good ! I knew there could be non cardiac reasons as well. 

Once again, very grateful for you all taking the time to comment. It helps !

Flecainide

by Gemita - 2020-10-12 02:35:51

Yes LondonAndy, clinicians often study our pacemaker downloads/any ECGs to see how effective a particular medication is for treating say an arrhythmia, or a heart condition.  Based on analysis of ECG, they may adjust our medication.  

My EP said that one of the reasons he wanted me to have a pacemaker was so that he could safely adjust my medication and then use the pacemaker to compensate for any deteriorating symptoms.  From personal experience taking Flecainide, I quickly developed a regular tachycardia after implant which miraculously stopped on cessation of Flecainide.  It was clear from my ECGs apparently that Flecainide was the culprit and was affecting pacemaker performance.  Now on minimum arrhythmia control medication, my pacemaker is finally able to pace me effectively.  So much can affect pacemaker performance.  However I accept that Flecainide can be a very good and safe med for many to treat AF.   Just proved pro arrhythmic for me

Flecainide

by AgentX86 - 2020-10-12 15:31:19

Flecainide is known to become proarrhythmic in many (most?) people eventually.  It's something that all EPs watch out for. Flecainide is one of the lesser antiarrhythmics and fairly benign as far as antiarrhythmics go.  Antiarrhythmics effectiveness is roughly inversly proportional to their safety and flecainide is near the bottom of the list.  If it had the side effects of more potent antiarrhythmics, it wouldn't be used at all because it can turn on you like a hungry cat.

If the purpose of the pacemaker was to monitor your arrhythmias, why didn't he use a loop recorder instead of going all the way to a pacemaker?  They do a much better job of recording electrical activity.

AgentX86

by Gemita - 2020-10-12 16:05:20

I wrote  "My EP said that one of the reasons he wanted me to have a pacemaker was so that he could safely adjust my medication and then use the pacemaker to compensate for any deteriorating symptoms" - deteriorating symptoms being dangerously low heart rates.  I did not say that the purpose of my pacemaker was to monitor my arrhythmias.

The main purpose of my pacemaker was for bradycardia, syncope, pausing and to safely administer higher doses of rate control meds for my AF with rapid ventricular response without dropping my heart rate too much.  It was not implanted to monitor my arrhythmias.  I had a loop recorder already in place at the time of pacemaker implant which I kept in place because of the exceptional ability of the Reveal Linq monitor to monitor my arrhythmias.  My loop recorder was removed when the battery ran out.