A Pacer Puzzler

Sometimes we see things on the monitor that while they look like things aren’t working correctly they actually are doing what they should.  Case in point from awhile ago.

The tech calls me and says, “Your patient in 75, they keep alarming for missing beats and pacer not pacing.  You going to call the doc?” as he hands me the following strips:

#1#2

I looked down, double checked and said, “Nope.  It’s working perfectly.”

In both strips you can see spots where it appears that the pacemaker is failing to pace, after 1st and 7th QRS complexes in strip #1 and after the 4th QRS in strip #2.  In each case you have a spike then a p-wave and nothing until a odd appearing PVC-like beat.  The tech pointed these out and I further reiterated that, “Yes, it’s working just fine.

But I had a cheat, I had read the interrogation report from when the patient had been admitted and knew what mode the device was set for, the tech hadn’t.  This is a pretty good example of a mode known as MVP, or managed ventricular pacing.  Basically this is a mode designed to reduce ventricular dysynchrony by allowing the heart’s natural conduction system to function while providing back-up in case of failure.  Excessive right ventricular pacing has been shown in studies to lead to congestive heart failure, increased incidence of atrial fibrillation, increased left atrial diameter and changes to hemodynamics and ventricular remodeling all of which can have detrimental effect on the patient and their quality of life.

In MVP pacing the pacemaker operates in AAI/R mode, as shown in both strips, with a set duration of time to allow for a ventricular beat.  If no beat arrives in the programmed time span the device will initiate a ventricular beat then return to the AAI/R.  If a beats are frequently dropped, usually 2 out of 4 complexes, the device shifts to DDD/R mode.  It will continue this way for a minute then attempt to return to AAI/R to detect AV conduction.  If beats are still dropped it will remain in DDD/R mode for increasing amounts of time, periodically checking for the return of AV conduction, at which point it will switch back to AAI/R mode.

Let’s break each strip down.

Strip #1:  starts with normal AV conduction in AAI/R mode and almost immediately, a beat is dropped and the device iniates the rescue beat.  It continues for 5 more QRS complexes until there is another dropped beat.  There is normal AV conduction for one more QRS then another dropped beat after which the device switches to DDD/R mode (it was too long to scan).

Strip #2: a little simpler.  4 normal QRS complexes then a dropped beat followed by a PVC, then another dropped beat.  Here you can see the device then switch into DDD/R mode due to dropping 2 out of 4 beats.

So, yes, the pacer was working exactly as it was supposed to.  I explained this to the tech and went on my merry way.  The next time he sees this he’ll stop to ask if they are set to MVP from now on.  Good learning moments come when you least expect them!

Sources:

Sweeney, M., Ellenbogen, K., Casavant, D., Betzold, R., Sheldon, T., Tang, F., & … Lingle, J. (2005). Multicenter, prospective, randomized safety and efficacy study of a new atrial-based managed ventricular pacing mode (MVP) in dual chamber ICDs. Journal of Cardiovascular Electrophysiology, 16(8), 811-817. Retrieved from EBSCOhost.

 Gillis, A., Purerfellner, H., Israel, C., Sunthorn, H., Kacet, S., Anelli-Monti, M., & … Boriani, G. (2006). Reducing unnecessary right ventricular pacing with the managed ventricular pacing mode in patients with sinus node disease and AV block. Pacing & Clinical Electrophysiology, 29(7), 697-705. Retrieved from EBSCOhost.

 

 

 

 

 

Meetings: Not a Prioirty

To: Unit Manager

From: Wanderer, overworked charge nurse

Subject: Monday’s Meeting

I guess one of the included functions in the Managerion™ 2000 automated management toolset randomly creates meetings and requires our attendance.  This would explain relative randomness and recurring frequency of such meetings and their lack of cogent concept or agenda.  Having meetings just to have meetings about meetings is pointless and a waste of all of our time.

In the last 4 meetings we have decided absolutely nothing, but keep referring to later meetings to “work out the details”.  Would it be so hard to make a decision?  Yes, you have multiple units that these decisions will affect, but sometimes you need to throw caution to the wind and make a decision – call it an executive mandate.  There is something to that y’know?

This said, I won’t be coming to any more meetings.  I’m not going to spend an hour each way commuting in to work for a meeting that lasts 45-60minutes and decides nothing.  It is not as easy as some might think.  Whether I drive or not it is at least 45 minutes in rush hour traffic and if I use transit it is even longer.  Now if we were going to decide something or the  meeting was going to last 2 hours, things might be different.  Also if I didn’t have to come back to work the night shift at 1900 it might be different as well.  But the last 4 meetings have done nothing of the sort.

I realize that it is part of your annual review to see how many meetings you presided over, ran or otherwise were engaged in, and I know management is in agreement that meeting indices are not quite what they should be for this fiscal quarter, but please, enough already.

So unless the next meeting will actually accomplish something, or is held in a local pub during happy hour, I won’t even be phoning it in.  I am a nurse, I take care of patients.  I am not a paper-pusher, drone, meeting junkie or have any aspirations to management  so just let me do what I’m good at – no more meetings.

Thanks!

Wanderer, overworked charge nurse

Maybe What It Could Have Been

I’m sitting out on my minuscule deck enjoying the remnants of the day and getting slightly misty-eyed. Can’t help it.

I hear the neighbor kids playing and having a good time. Normally, they annoy the heck out of me, but it seems fitting. I hear their parents further in the distance, laughing, telling tall tales and generally having a good time as well. It’s all so Mayberry-like. Sure I can’t understand a word of what they say, but happiness and joy are universal in their sound.

But it is this time of the year, August. Too many bad memories, too much repressed pain and anger, but I thought I had it all licked, tamped down, under control. But no. Not even close. It’s fucked up how things that happen around you can re-open old wounds with a violent force that takes your breath away. A co-worker recently lost her babies in a somewhat similar fashion to my wife and I and that brought all of it back with a vengeance. That day I sat in a cold sweat, heart racing recalling the feelings of the 10 days our daughter was alive. I shivered through the cold icy grip of fear as I vividly recalled walking into her room, crowded with staff trying to bring her back and having to tell them to stop and let her go. Even as I write now, underneath the beer I can feel the shakes, the racing heart and cold pit in my chest. It never seems to go away completely.

So I laugh and joke it away, smile through the pain deep inside. I sit and wonder if I need to go back to the numbness of chemical happiness because at least then I didn’t feel anything. I sit and worry if there is something wrong with us, with me, how almost 5 years later,with no contraception there hasn’t even been a scare. I feel like we had two chances but they failed and we don’t get a third. It sucks. The sounds of family seem so comforting, yet so alien. Like something out of reach that we will never know.

We would have been having her 5th birthday this weekend, surrounded by friends and family, all so Mayberry and suburban happiness. Instead I’m sitting here listening to someone else’s family having a good time and pondering what it may have been.

Thanks for listening, I’ll be back to normal soon.

Are we Evil?

“Why would you choose to do this job?  I know you’re killing people and hiding the bodies.”  such was the thought process of the paranoid post-op patient.  No matter what we said, what we did, the delusion was so real to them that while they got along fine with day shift, there was a lingering mistrust of the night shift because we were killing people.

Sometimes I do question the things we do, the horribly invasive things we do, breaking chests open, sticking needles in veins, catheters in any numbers of openings, slice, sew, defibrillate.

And heal.  That answers the question doesn’t it?

bonus…

It’s just too awesome not to include…