student with a question-

wv_nurse 2003 · Mar 21, 2004

It is true that all cardiac cells have the potential to initiate electrical activity. The SA node (pacemaker) has an intrinsic rate of about 60-100 impulses per minute (the basis for "normal" heart rate). If the SA node fails (for any number of reasons)--the "pacing" responsibilities drop down to less reliable cells with slower intrinsic rates: {follow normal cardiac electrical conduction patterns}: cells located in the AV juncion with a rate of 40-60; cells located in the ventricles themselves with a rate of 20-40. Consider it your heart's "back-up" plan.

Electrical signals in PEA can originate in any of these areas--and thus will determine the rhythm seen on the monitor. (If its the SA node firing--the PEA will be a sinus rhythm--I will guess that is rare). Usually PEA comes from a lower pacemaker--but depends on the underlying pathology that caused the PEA.

Hope that helps!

obeyacts2 · Mar 23, 2004

It is true that all cardiac cells have the potential to initiate electrical activity. The SA node (pacemaker) has an intrinsic rate of about 60-100 impulses per minute (the basis for "normal" heart rate). If the SA node fails (for any number of reasons)--the "pacing" responsibilities drop down to less reliable cells with slower intrinsic rates: {follow normal cardiac electrical conduction patterns}: cells located in the AV juncion with a rate of 40-60; cells located in the ventricles themselves with a rate of 20-40. Consider it your heart's "back-up" plan.
Electrical signals in PEA can originate in any of these areas--and thus will determine the rhythm seen on the monitor. (If its the SA node firing--the PEA will be a sinus rhythm--I will guess that is rare). Usually PEA comes from a lower pacemaker--but depends on the underlying pathology that caused the PEA.
Hope that helps!

Thank you for answering my question. Laura

rnmaven · Mar 25, 2004

I was hoping some of you cardiac folks could help me. I am in Physiology and we just finished a unit on the cardiovascular system. I came up with a question my instructor couldnt answer Our text was discussing the SA node and how it is the pacemaker for the heart. The text also said other cells in the heart are capable of generating action potentials as well. My question is: when a patient is in PEA, is this what is happening? Are these other cells trying to fire action potentials and take over for the SA node? Our text isnt clear on the subjuect and I have been looking around in Taber's and on some sites but so far all I have found is how to treat PEA, definitions of Pea, etc. I am curious so let me know. Believe it or not, my physiology instructor didnt know what PEA was I couldnt believe it.
Laura

Laura,

Maybe you better send your instructor the ACLS guidelines......maybe the algorithm for PEA will help him/her understand the concept. That's why you have to have a documented flat line to be actually considered dead!

Good luck in school.

bemory · Sep 24, 2004

My patient also had PEA- we were monitoring her heart rate which was normal and then when it slowed, we checked in on her and she had passed. She was very dehydrated and also was spetic.

The heart has a plumber and an electrician. The plumbing stopped though the electrician had not. The charge did not cause the heart pump and thus PEA. I learned that the reason the heart continues to charge is because our cells are comprised of water and that it carries the charge for a little while though the heart does not pump anymore. This is just something that I was told in school and later in an EKG class. The reasons of a cardiac tamponade, and possible PE are new to me but I wouldn't rule it out. There is a good pocket book called EKG's made easy that explains PEA also.

I know this sounds like a silly way to explain it but thats the best way I learn complicated stuff. If anyone has a good acronym for something pass it along:rolleyes: