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:


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!


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.






Question to the Experts

Awhile ago I’m sitting charting when the tele tech comes out of his cubby and says rather excitedly, “93’s rate dropped to 27 and is staying there!”  I pop up, walk over to the room and and see my patient sitting at the side of the bed with a look that says, “What do you want?”

“Do you feel OK?” I ask as I’m slapping a BP cuff around his arm.

“Feel fine.”

“Not dizzy, light-headed?”  I press.

“Nope, nothings changed from when you were here last.”  he says as the BP pops up 144/72.

“Your heart rate dipped into the 20’s and hung there for awhile, that’s all.”  I reply.

Here’s the funny thing though:  he had been doing this for days.  No problems with the low pulse at all.  Peeing fine.  No light-headedness, dizziness, auras or any other weird lack-of-perfusing the brain problems.  Only problem was when he moved about too much, he turned a lovely shade of eggplant purple.

Telemetry was showingwhat appeared to be a slow atrial fibrillation, but with his size, it would not have surprised me it if was a combination of junctional and ventricular escape rather than the a-fib due to the morphology of the QRS complexes.  Even with that in mind though, it could have been a-fib with a bundle branch block.  Then by luck, the morning before he was going to get a pacemaker the tele tech and I were chatting and examining his rhythm when we were able to get this shot.

click for largerIt starts with a PVC, then a sinus beat and another PVC.  Then it starts to get funky.  The deflection of the QRS complexes shift in every lead except the V-Lead, flipping opposite from what they had been doing.  There wasn’t slowing of the rate that could be coupled to this flip as he had gone lower several times during the night and his strips hadn’t changed like this.  Looking back through, we noticed that he had been doing this all along, but had never captured it on paper.

So why question becomes:  what the hell is going on here?  Am I looking at a junctional/ventricular escape type of rhythm?  Or an intermittent right/left bundle?  And what could be causing this transient shift in axis, especially with no complaints from the patient?

And for what it’s worth, he got a pacer and looked much, much better the next day.  But I’m still baffled.  Any help?

A Happy Hospitalist: Is Telemetry Overused?

A Happy Hospitalist: Is Telemetry Overused?.

In a short answer: yes.

Does an elder with stable chronic atrial fib being admitted for a UTI need tele?  Nope.  ETOH withdrawal without cardiac history?  Nope.  Too often folks admitted to tele don’t truly need it, and those that may benefit, don’t get admitted (at least right away…).

Happy makes the case of a patient having 12-beat run of SVT.  Remember, supraventricular tachycardia and ventricular tachycardia are 2 very different beasts.  Any good tele nurse should know this.  One is an abberrant rapid rhythm, that when it is self-limited while notable, is not life threatneing (SVT).  The other, is the same way when self-limited, but can be a very bad thing if not (VT).

If it was my patient who had  a 12-beat run of SVT what would I do?  Check them, make sure they’re ok.  Document it and go on my merry way.  If it is something that is happening regularly and with increasing frequency, I might text page the doc an FYI.  But an isolated 12-beat run isn’t even enough to get my heart rate up.

On ther other hand, the delirious UTI patient with a pacemaker on tele who spends the entire night ripping tele leads off may cause me to call the doc for a “d/c tele” order though!

EKG of the Week #1

click for larger view

Pretty classic example of failure to sense and failure to capture.

As you can see, the pacer is firing but there is no response from the heart.  No P-waves, no QRS complexes, just lone pacer spikes hanging out.  This is classic failure to capture.  Possible causes of this can be a fractured or dislodged lead, battery failure or electrolyte abnormalities among others.  Luckily in this case the patient has an intrinsic rhythm that is probably perfusing them.

The second item shown is failure to sense.  Notable for this is the pacer spikes in the ST-segments.  Failure to sense is exactly what is says, the pacer is failing to sense the cardiac cycle and inappropriately pacing.  Again, luckily in this case the pacer is not capturing so the inappropriate pacing is not causing issues.  The biggest problem with this failure is inappropriate firing when the heart is not quite yet refractory possibly initiating ventricular arrhythmias.  Causes of failure to sense include lead issues (dislodgement, fracture or poor positioning) or sensitivity issues requires a change to sensitivity.

In this particular case, it appears the patient is in atrial fibrillation, which may be causing issues with both capture and sensitivity.  The erratic electrical signals emanating from the atria may be throwing off the pacer, but many times they are programmed with this in mind.  For nurses the important things to remember is to check on the patient when the pacer is acting up and ensure they are stable.  Past that, with permanent pacemakers, we need to get the cardiolosit involved.  If it the nurse who is running a temporary pacer at the bedside, adjustments to both output and sensitivity may be required to ensure adequate sensitivity and capture (but that’s a whole other ball-game!).

Here’s what a pacer strip should look like:


Each spike has a corresponding activity, just like it should.

A Never Event?

According to CMS, we experienced a “Never Event” last month.  But the even itself illustrates in my mind the flaws inherent in the whole concept of a “Never Event”.  Theoretically, the idea is agood thing.  There should be events that could occur while a patient is admitted to a hospital.  Some things should never happen:  like wrong blood, surgery on the wrong part of a patient or abduction of a patient of any age.  Some stretch the bounds of rational thought though.  The one that comes to mind is patient falls.

In the hive mind of CMS, patients should never fall.  Once again, theoretically, not to mention from a public relations standpoint, the argument is sound.  What they and the public tend to forget, that unlesss someone it at the bedside 24-7, falls will occur.  You can follow every published guideline out there.  Scheduled toileting, hourly rounds, bed alarms, reduction of the use of medications that can cause or enhance delirium are all really great ideas and have been proven to reduce falls.  But the bottom line is that when our elders, especially those that may have dementia tned to fall.  Add illness, strange environment, odd noises, unnatural schedules and new medications and you cook up a recipe that could conceivably lead to a fall, in spite of any and all safety measures we as caregivers may take.

But people fall.  Sometimes people fall and there is nothing we can do about it.

Exhibit A:

click for larger size

click for larger size

Anyone who knows EKG tracings can immediately grasp the bad things going on here.  But for those who may be a bit rusty, let me break it down for you.  The patient is rolling along in normal sinus rhythm until they get hit with a R-on-T PVC (a premature ventricular beat the falls when the myocardium is not yet fully repolarized, see below) initiating a run of Torsades de Pointes.  Torsades, meaning “twisting of the points” is a life-threatening ventricular arrhythmia that can rapidly devolve into ventricular fibrillation and death.  It is a form of ventricular tachycardia (VT, V-Tach) characterized by the rotation of the complexes around the isoelectric line illustrated by the increasing/decreasing amplitude of the waves in a near sine-wave pattern.  Treatment in an emergent situation is the following of the V-Tach leg of the ACLS algorithms, although usually a bolus of magnesium sulfate can terminate this as well.  Usually though, when we see this though, the proverbial shit has hit the fan.

In this particular case the patient had been ambulating in the hallway and flipped into Torsades.  The red mark is about where we figure when he hit the floor.  Not for sure, but the timing seems about right.  Now what would CMS say about this?  The patient was awake, alert and oriented x 3, ambulating under his own power when he fell.  So it is still a “never event”.  And this is why a one-size fits all labeling makes no sense.

First, does this mean we shouldn’t let patients ambulate?  They might fall.  Second, should we not give medicatons that may cause arrhythmias like this (more below…)?  They might fall.  Third, should we not anti-coagulate patients who are under treament for atrial fibrillation and thus increase their risk of bleeding with a fall?  Painting in broad strokes doesn’t always work.

Unfortunately, the patient had previously been in atrial fibrillation and been anti-coagulated with warfarin for an INR of 3.2.  He had been cardioverted out of a-fib into sinus earlier in the day and was intiating Tikosyn therapy.  The truly unfortunate part is that when he went down, it was like a tree falling in the forest:  straight back off his heels with his head striking the floor.  CT showed a massive cerebral bleed as a result and family chose to withdraw support allowing him to pass.  So this is a huge “never event”, as per CMS, “Patient death associated with a fall while being cared for in a healthcare facility.”  If he had not been ambulating, odds are pretty good that he would have made it out of the code, as there was a spontaneous return to sinus rhythm right after the scanned strip ends, with spontaneous return of circulation as well.  But since he fell in the hallway and hit his head, the deck was stacked.

As for the medication, Tikosyn (dofetilide) is a Class III antiarrhythmic medication that works by prolonging the cardiac action potential duration.  One major hallmark is that it subsequently prolongs the QT segment.  A prolonged QT interval increases the risk of ventriclar arrhythmias as the repolarization of the myocardium happens at different rates allowing myocytes that have already passed their absolute refractory period to depolarize early and possibly causing a re-entrant phenomenon, kind of like a viscious circle.  The FDA actually mandates that anyone being started on Tikosyn gets themsselves a 3 day vacation on a telemetry floor for this very reason.  Usually we monitor the QT/QTc closely in these patients, obtaining a baseline, then 12-lead EKGs 2 hours post-dose to ensure that the QT/QTc is still within limits.

So was this a “never event”?  Probably.  Could it have been prevented?  Probably not.  There were too many variables in play to do so.  Sometimes shit just happens, no matter what we do.

Just another night.

It was just another night.  Not too out of the ordinary.  My patients were all tucked in, chart checks were done, I had even had time to go off the floor for a half hour to eat while watching Sportscenter.

Out of my 4 patients, only 2 were on telemetry therefore, only 2 required the 4am vitals.  That I figured, could wait until 4:30, maybe even 5am.  Heck, why not let them sleep a bit?  One had come in at the god-awful time of 0-dark-thirty the previous night and had unfortunately kept the other up most of the night in the ever time-consuming process of admission paperwork (even though I am a bit of a whiz at it…).

I had been keeping my eyes and ears open, slowly watching the little green squiggles of the EKG lines trace their way across the monitor, trying valiantly to stay in some semblance of wakefulness.  One of them, Mrs. S., I had been keeping a closer eye on than usual.  Nice older lady, in with pneumonia, A-Fib with RVR and ground level fall.  The pneumonia had been getting better, instead of crackles and wheezes all the way into her upper lung fields, they had retreated down to the bases, still there but not as bad as they had been.  Her A-Fib had been wrestled under control with a little help for our friends Cardizem and metoprolol, ususally she lived in the 90-110 range, give or take, even lower when she slept.  All night, she kept coughing, that pneumonia cough, it never really brings anything up, but never really goes away.  Just nagging enough to keep her partially awake.

But tonight it was her rate that was on my mind.  All night it had been creeping up, never drastically, but like the cough, just enough to keep my attention.  It was 3:30 and she was hanging out in the 140s now and had been for awhile, so I was starting to get ready for some meds.  She had just rung the bell and our oh-so enthusiastic aide went to see what she needed, (mind you, it was that kind of a night for everyone).

As she comes out she says, “Hey Wanderer, she says she’s feeling a little short of breath, not too good at all.”

“I’m on it,” was my reply.  As I’m heading into the room the “oh- shit!” alarm on the monitor starts going nuts.  “Hey Wanderer,” someone shouts from the station, “That’s your lady, she went up to like 180 and is sustaining in the 160’s!”

“Shit.”  I mutter to myself as I bust into the room like Patton himself.  She looks up at me with that worried scared face and says after she stopped coughing, “Y’know, my cough is getting worse and I don’t really feel like I’m getting a good breath.  And my heart feels like it’s beating really fast.”  I can hear her lungs from the foot of the bed, they sounded like Sponge Bob could live inside the ocean that was filling her pulmonary system.

Cool as a cucumber, but starting to shake just a little, I said, “Well let’s check this out,” and start hooking her up to the in-room monitor.  The monitor starts bing-ing the “oh shit!” alarm again: rate in the 160’s.  I reach down feel her radial pulse, yep, feels about right.  I take a listen with my stethoscope.  Yep, wet, wet, wet breath sounds all the way up, from the bases to the tops.   And her cough had turned from non-productive to a more milky, frothy kind of gunk.  “Not good Wanderer,” I said in my head, “I need to get the rate down.”  So I sit her up in bed, turn the 02 up a little more and have her take some nice slow breaths and tell her, “I’m going to go grab some medicine to slow your heart a little OK?”  Hoping that the adrenaline now pumping full-bore doesn’t make my voice quaver at all.  She nods.  “I’ll be back in a moment, call me if it gets worse.”

Out to the nurses station, I grabbed the phone to page the intern.  With the page on the way I went into the med room to grab the metoprolol I had intended to grab before the aide grabbed me.  Pull the med out of the Pyxis, override for Lasix and my pager goes off.  “413”  code for phone call.  Pop out of he room, “It’s Dr. Night-Intern on A” someone says.  I pick it up, “Dr. Night-Intern, Sir?  You guys are still following Mrs. S, right? came in with pneumonia and A-fib with RVR?”

“Ahh…” I hear pages rustling oint he background, “Oh,yeah,we still are…”

I cut him off, “I think she’s trying to flash over on me, she has frothy sputum, lungs sound wetter than they did at start of shift and her rate’s been sustaining above 160 and has gone as high as at least 180.  I have metoprolol PRN, but can I get an order for some Lasix to help get the fluid off?”

“Ummm, uhhh,” I’m watching the monitor, rate is 170 now, “Well, what’s her renal function like?” he comes back with.

“BUN and Creat are WNL, K this AM was 4.3, she got 40 mg of IV Lasix this morning.” hoping he hears the urgency in my voice.  I really don’t want to have to call a rapid response now.

“OK, did the Lasix work this morning?”  I smack my hand against my head, time is not on my side right now I’m thinking, “Uh yeah, sounds like it worked great, she put out approximately 1500ml for day shift today.”

“OK, go ahead and give 40mg IV times 1, now…” he says.

I cut him off, “OK, what’s your P#?”

“Oh, does she have labs this morning?” he asks.

“Nope, no labs, want one?”

“Yeah, grab a comp and a mag this AM.”  he comes back with, “P# is 1234567”

“OK, thanks Dr. Night Intern, I’ll call ya’ if you I need anything else.”

I look, it has taken all of 2 minutes, tops, but felt like a near eternity.  I had already pulled the Lasix up after he had said “OK” (and who said we shouldn’t multi-task?).  I looked up at the monitor as I headed back towards the room, looked like 160’s still, bumping to 170.

“OK Mrs. S, I have some medication here for you, gonna’ put it through your IV , OK?”  She nods as we go through the JCAHO rigamarole of identification – name, DOB, cat’s name, mother’s maiden name and shoe size in Europena sizing – to determine that it really is Mrs. S.  I grab a quick BP as I start to give the metoprolol.  When the machine stops cycling it shows 140’s over 100’s.  “Well, that ain’t good” I think to myself.  I’m a little calmer now, but still riding the crest of the adrenaline surge.  I finish pushing the metoprolol, as the machine cycles again, now we’re down to 140’s over 80’s, not great but better.  Heart rate is already starting to drop, now sustaining in the 140’s.  I push the Lasix and say, “I apologize to do this to you at this time of the morning, but it will help get some of that fluid off your lungs.”

She says, “It’s OK, it’s what needed to be done.”

I look at the rate, now we’re into the 120’s, respirations are down to about 18-20 and BP is running near her baseline of 120’s over 60’s.  She even looks better already, that worried face is gone, in it’s place relief.  “I’m just going to hang out here for a couple of minutes OK?  Just to make sure we’re doing better.”

She looks up and says, “It’s OK, I’m already feeling better now.  I feel like I can breathe a little better.  I’m glad you were here to help me.”

“I’m glad I was too.”  As I said that, I was thinking to myself that if I was as good of a nurse as you think I am, you wouldn’t have been in this situation.  It’s really my fault that this happened at all, I wish I had the balls to say.
At midnight she had PO metoprolol due, but with holding parameters, HR <60, SBP <90.  Being the ever-prudent nurse I am, I checked both prior to giving the meds.  HR had been 110’s, but SBP was 88, so in concurrence with the parameters, I held it.  Now, I know that there is no way to prove that was the precipitating event, but I felt deep down that maybe it had something to do with it.  I talked it over with my colleagues and they agreed: it was a crap shoot.  The pevious night her SBP had been fine but the dose dropped her 10 points and she had felt a little goofy and wobbly when she was standing, so I didn’t want to repeat that, but I wavered knowing that the primary reason for giving her the med was rate-control.  In the end I didn’t give it.  That’s why I kept my eye on the monitor all night long.  That’s why I was coiled and primed, ready to run in, because I had that feeling in my gut that something might be afoot.  It was a heck of way to re-learn a lesson, or at least give me bigger pause the next time to reconsider the meds I am giving.  It taught me a lot about nursing judgment.  We’re entrusted to make decisions that have life-changing effects on our patients and even when we think we’re making the right choice, we’re not always.  I know that judgment gets better with experience but sometimes you get burned. The good thing though,  was that it was caught early and treated before it got worse. Besides that, I realized that if this had happened less than 6 months ago, I would have called rapid response.  Granted, I would not have been wrong to do so now, but I felt comfortable in not calling the team and managing it myself, knowing I had backup a mere phone call away.

As I finished charting the episode and my adrenaline started to fade, the monitor tech came back to post the strips and asked, “Did you see how high your lady’s rate went?”

“No, I hadn’t.  How fast?”

“It topped out at 201 and spent a lot of time in the 180’s.  Is she OK now?”

“Holy crap, any wonder why she didn’t feel that great!  She’s doin’ OK now.  Nothing a little metoprolol and Lasix couldn’t fix!”  I said with a grin and went on my way.

And the night continued.  Just like any other night on the floor.

Inappropriate ICU Transfer of the Week

When folks need to go to the Unit, whether it is an evolving MI, (non)lethal arrhythmia, hemodynamic instability or they just need that higher level of care, we can’t wait to get them off the floor. Last thing anyone on our floor wants is a truly unstable patient lingering in one of our rooms when they needed to be the Unit 20 minutes ago. Sometimes though, you just can’t seem to convince the docs that they need to go and in the same vein, those that really don’t need to go, get sent.

We had a couple of instances of that lately. First, we called a Code on a guy who vagaled on the toilet. He was down to the Unit in less than 15 minutes, albeit already awake and laughing with the transport nurses as he went. At the decision time though, he needed to go. Now.

On the other hand is the patient who is stable but the docs are convinced they require  the advanced monitoring care of the ICU. This happened just the other night.

Let me remind you, we’re a cardiac unit. We deal with post-PCI patients, pacers, rule out MI’s, pre/post-op open hearts, CHFers, arrhythmias (like atrial fibrillation with rapid ventricular response) among other things – like being the largest unit in the hospital and getting overflow patients. When it comes to all things cardiac, we’re the place to be. Guess that’s why the sign over the entrance to our unit says “Cardiology/Cardiac Surgery”.

Anyway. My colleague’s patient was post-chole or some other laproscopic surgery. Nothing too hot and heavy. She goes in to asses her patient (who’s not on tele) and notices her heart rate is rapid and irregular. Being the good cardiac nurse she is, she grabs a12-lead EKG and voila’ – a-fib with RVR. She calls the surgical resident on call who orders some metoprolol to slow down the rate and eventually a diltiazem drip. No biggie to us. We do this all the time. Heck, with our fresh hearts we have an A-Fib protocol where we don’t even have to call the surgeon if the patient goes into fib, as long as they’re hemodynamically stable. We just follow the protocol.

In this case, after the drip was started, blood pressures were 110’s over 70’s, rate in the 80-90’s, good perfusion (warm, pink and intact), making urine, not even short of breath. Totally manageable on our floor. But the surgical resident still wants to transfer. My colleague tries to suggest that it isn’t needed. She did everything but come out and say, “Y’know what? She’s stable. Her rate’s good. She doesn’t need to go.” Not that it would have done any good. So off she goes at 0630 down to the Unit. Her rate on arrival to the unit was 70’s and it looked like her heart was already trying to convert back into normal sinus.

I looked at the ICU nurse and said, “Ten bucks says she’s back up by the end of the day.”

To which she replied, “End of the day? She’ll be back up by noon!”

“Right,” I retort, “if they haven’t given her room away…”

It’s a Murphy’s Law kind of thing: they go when they don’t need to and stay when they do.

And for all you soda drinkers out there, here’s a little bit of science to enliven your day: “What happens to your body if you drink a Coke right now?” Now, off to the fridge, I’m kind of thirsty…