Implanted D-Fibs and PEA's

[runswithneedles]

Dang im just on a roll this week with decent cases. Kudos for me. More to review with the fine folks of this forum.

Anyways we took a patient from ICU to hospice tonight. He was going for end of life care s/p caridac arrest and revival. In short EMS brought the body back but mind was a veggie.

Anyways after learning he had an implanted internal defibrillator which was disabled via magnet I was looking through his H&P. It indicated upon EMS arrival that he was in PEA. Can a implanted dfib cause a rythm like that should it get stuck in pacer mode or malfunction or in any way shape at all?

If you guys need any additional info feel free to ask. I actually have a decent H&P this time :-)

Edited January 28, 2012 by Mike Ellis

[island emt]

If the pt had a magnet placed on the AICD then it was no longer functioning. Hence the pt own heart was the only source of power

. If the heart gave out then that could have been the pt's wishes . Thats why the magnet.

Lose the "anyways" it makes you appear to be a 12 yo

[nypamedic43]

As island pointed out, if the internal defib has been deactivated by magnet, the heart is under its own power. I am going to guess that it was the patients wish, as they are going home on hospice for end of life care.

As for the PEA (pulseless electrical activity) , regardless of whether the internal defib is active or not, the patient can still go into a PEA. What this means is that the heart (or internal defib) is producing the electrical pulses it needs to make the heart pump....but the pump isnt doing what its supposed to be doing, pumpng.

[systemet]

Can a implanted dfib cause a rythm like that should it get stuck in pacer mode or malfunction or in any way shape at all?

Can a pacer firing continuously cause PEA? Well, you can have electrical capture without mechanical capture. I guess you could technically call this PEA, although it would be unnecessarily confusing.

You can have "failure to sense", where a demand pacemaker doesn't recognise the patient's intrinsic complexes. This could cause a pacer to pace continuously, but this would be a rare event.

In both these situations, you'd want to be careful to identify the underlying rhythm. It may be VF, and amenable to defibrillation. (Not that this would be indicated in this specific patient).

* Just a quick note: Pacemakers are triggering cardiac depolarisation, they're not reducing energy consumption. They cause the cardiomyocytes to depolarise, just like an SA impulse, ion gradient's still have to be restored, ATP has to generated to allow for cross-bridge cycling, etc. They're there because there's some degree of dysfunction in the cardiac conduction system that's preventing an organised sequential and synchronous contraction.

Edited January 28, 2012 by systemet

[paramedicmike]

First I think we should clarify just what type of device was implanted. The OP mentioned an implanted defibrillator. All the replies so far have talked about pacing. Given the way the OP was presented I can see the confusion.

There are different types of devices out there. There are implantable defibrillators which are separate from implantable pacers. There are combination units that can both pace and cardiovert/defibrillate. Knowing what it was will help answer your question.

If it was simply an implanted defibrillator then chances are pretty low that it would cause a PEA in a patient. Implanted defibrillators detect abnormal rhythms (e.g. runs of ventricular tachycardia) and either cardiovert or defibrillate.

Implanted pacers simply provide pacing support by mechanisms already well presented by Systemet.

Dual purpose implanted pacers/defibrillators can both pace and cardiovert/defibrillate as necessary.

So, as to the OP's original question, if it was a single purpose implanted defibrillator it's not going to get stuck in pacer mode. It's also not going to cause a PEA in an individual. If it was a pacer or a combination pacer/defibrillator please see Systemet's response.

This is another example of knowing the equipment involved (much like the vent in your other scenario). While it is not uncommon to come across new equipment on the job, doing some research on equipment you've encountered before posting your questions may come in handy to help clear up some of your confusion ahead of time.

All that being said, though, this was a good question.

[runswithneedles]

Thank you very much. For some reason I had a thought that it could. But after systemets explanation I now understand how a pacer works.

And how do you re edit a post? I cant find it. Island pointed out something and its going to bother me if I cant correct it.

Edited January 31, 2012 by Mike Ellis

[paramedicmike]

If you wait too long you can't edit a post.

[systemet]

For more reading in this area, check out this webpage:

http://missinglink.u...odule/index.htm

Or this .ppt

http://www.google.ca/url?sa=t&rct=j&q=pacemaker%20classification&source=web&cd=3&ved=0CDMQFjAC&url=http%3A%2F%2Fwww.coronaryheart.com%2FPowerpoint%2Fpacemaker%2520overview.ppt&ei=4rcnT7GbNeP34QShs8HpAw&usg=AFQjCNGKDiJhpgGCOhReQ8_Inofl6UFICg&cad=rja

Or this:

http://www.google.ca/url?sa=t&rct=j&q=pacemaker%20classification&source=web&cd=7&ved=0CE8QFjAG&url=http%3A%2F%2Fmedresidents.stanford.edu%2FTeachingMaterials%2FPacemakers%2FPacemakers%2520Handout.doc&ei=4rcnT7GbNeP34QShs8HpAw&usg=AFQjCNH4H8NUOOd8gZz9SiyAqDFHhvHNGQ&cad=rja

Edited January 31, 2012 by systemet