How does my PM work ?

I went to my cardiologist ( NEW one) on Monday. I asked about my pm. He told me it does not "run" all the time, just when needed
That seems odd to me. I was diagnosed with CHF and cardiomyopithy, with an RF of 15%, in June 2015 and was told that a PM was needed and if it didn't work a full transplant would be necessary. If the Pm was necessary, when does it work ? I recently went to the hospital for "major" pain (which they could not diagnose, why), but they did an echo/scan and it seems that my RF is now @ 30-35 %. Big jump , I think. So what exactly is the PM doing ? It is a Viva Quad XT CRT Defibrillator, from Medtronics.
Suz2015

4 Comments

great improvement

by Tracey_E - 2016-03-16 01:03:34

That's a nice jump in ef!!!

You have three leads. I mostly only know how two lead works but I can give you part of an answer...
the atrial lead is there to kick in if your sinus rate drops below your minimum, probably set somewhere around 60. It's not set by the minute but rather by the second so that means if you go a second and don't beat, it will send a signal that mimics what your heart should have done, the heart reacts by contracting.

When the atria beats, it should send a signal to the ventricles to beat immediately. The pacer is still watching. If the ventricles don't keep up, it kicks in again with ventricular pacing this time so the ventricles keep in sync with the atria. This is where I'm a little fuzzy on the difference between two and three lead, I just have the one. In your case, it will pace both ventricles to keep them in sync.

The defib part is there in case you go into a dangerous rhythm, it can shock you out of it.

The pacer will always give our heart a chance to work on its own before pacing, that's what they mean when they say on demand. It will watch all the time, but only pace as needed.

Resynchronization

by BillH - 2016-03-16 02:03:38

CRT - Cardiac Resynchronization Therapy

The most common PM's are 2 chamber. And they work like Tracy said.

Depending on the particular needs it can monitor the normal heart beat trigger, the sinus node. And if it fails to fire then it can pulse it. That fires the atria.

After the atria fires the signal then goes through the AV mode and then simultaneously the two ventricles.

If the signal does not get to the ventricles then the 2 chamber PM will trigger a lead in the right ventricle and it starts to squeeze and then the pulse moves through to the left ventricle and it starts to squeeze.

While that is usually effective it is not as efficient as when both ventricles contract at the same time. That can be a particular problem for people like you.

With CRT there is a lead in both ventricles and when it has to fire it causes both to contract at the same time.

Thanks

by Suz2015 - 2016-03-17 10:03:40

While I'm not sure I got all that, (still new to this "world")
I do appreciate all the information ! I do have a little better understanding of what is going on....

animations

by Tracey_E - 2016-03-17 12:03:23

I love these videos that explain how the heart beats, most major conditions that result in getting a pacer, how pacers work
http://health.sjm.com/arrhythmia-answers/videos-and-animations

if we throw around terms you don't understand or say something that doesn't make sense, don't be shy about asking! Also, there is a link to a list of abbreviations on the left side of this page.We use a lot of abbreviations :)

What you are calling RF is, I believe, EF, or ejection fraction. That's the percentage of blood that gets pumped out of the heart with each beat. 55-65 is normal. With myopathy the heart loses the ability to squeeze like it should, that's why your EF dropped so low, the muscle isn't contracting enough to force the blood out. Your device can't make the heart beat stronger or contract harder, but it tries to improve things by keeping the left and right ventricles beating in sync. And it seems like it's working for you, that's what counts!

You know you're wired when...

You make store alarms beep.

Member Quotes

I have had my pacer since 2005. At first it ruled my life. It took some time to calm down and make the mental adjustment. I had trouble sleeping and I worried a lot about pulling wires. Now I just live my life as I wish.