AndersonRecordingEdit - ERM 9.5.2024

Hello, my name is Elizabeth Maginot. I'm one of the Surgical Education Fellows at Behind the Knife and General Surgery resident at the University of Nebraska. Today I'm joined by Dr. Nathan Anderson, Associate Professor in the Division of General Internal Medicine and Hospice at the University of Nebraska in Omaha.

Today we're going to be discussing atrial fibrillation in the post operative setting as part of our Med Surg Consult Series. Thank you for joining us, Dr. Anderson. You bet. Appreciate the invite and I'm excited to be here, so appreciate it. We're excited to have you. So we're going to dive right in. We'll kick off with the case.

You are transported to an alternate reality. You're a surgical intern here. You're taking care of a 68 year old gentleman with history of hypertension and diabetes who just underwent coronary artery bypass graft surgery. It's post op day two and you get a page that the patient is now newly tachycardic into the 150s and the monitor's reading AFib.

How are you going to approach this patient? I love it. I love diving in

a real case and we'll try to make some practical paroles and management one on one kind of stuff here. So very first thing to note when you get this page is talk to the nurse and get some final signs because you need to try to triage this patient, try to figure out, is this patient stable or is this patient unstable?

So certainly going to change your, your management quite a bit here too, okay? Second thing that you want to do is you should always question the diagnosis. Okay. The, the monitor that's reading atrial fibrillation, I have seen this happen several times where, um, the monitor compared to what you actually get on a 12 week EKG is different.

You're going to want to get an EKG, uh, quickly. So when you get the EKG, first thing I want you to look at is, you know, confirm that it's in a regularly irregular rhythm. And I want you to look for, is there clear delineated P waves before every QRS? Okay. If there's not, and it does appear irregularly irregular, then yes, it does seem like we have, uh, um, atrial fibrillation with rapid ventricular rate.

Talk about our management here. I personally have been

fooled, and in fact the computer I've seen recently when I was in service, the computer read it as APO with RBR, and actually this patient had just really prolonged spurt degree AV block, or sometimes multifocal atrial tachycardia, or other kind of, uh, atrial arrhythmias can mimic atrial fibrillation.

Yeah. Definitely need to get your EKG and vital signs right off the bat on the way to bedside. How common is AFib after surgery? In general, uh, atrial fibrillation is very common. Um, we see this very frequently, especially after a cardiac surgery. Um, I think the incidence is about 30 percent after cardiac surgery.

Where after any other thoracic surgery it's, you know, 10 or 15 percent. Besides, obviously we mentioned cardiac surgery as being a major risk factor for developing atrial fibrillation. Any other major risk factors to note? Yeah, for sure. This person was just at an open heart surgery and had a probably a three vessel cabbage or something or two.

So, he's coming off the pump recently. There's inflammatory

responses that can lead to, you know, atrial tissue irritation. There's oxidative stress. There's perhaps electrolyte abnormalities that's been going on. Presumably, this patient probably got a lot of blood products, hypocalcemia, hypokalemia, hypomagnesemia can all certainly increase risk of AFib.

Um, certainly just the stress of surgery itself and increasing the autonomic nervous system between the sympathetic and parasympathetic nervous system can increase the risk of developing atrial fibrillation. And then, you know, this is a 68 year old, so atrial fibrillation is more common as we age. You have hypertension and diabetes like this guy has, says he has probably some increased risk of having atrial enlargement or scarring, perhaps increased atrial pressures if he's gotten lots of fluids here.

Perhaps he has a history of pre existing atrial fibrillation, perhaps this is new onset atrial fibrillation. And then we also need to consider some other bad things like, uh, maybe he's developed a pericardial effusion. Or perhaps he's newly hypoxic that's

aggravating or making this worse with his recent intracardiac surgery here too, so.

You, you get back your EKG. It confirms, uh, AFib with rapid ventricular response. His rate is 152. He is hemodynamically stable, so blood pressure is 123 over 80. He's doing good. He's talking to you. He really is not having any symptoms when you see him. And what is your initial treatment in the post cardiac surgery patient with post operative AFib?

Okay, perfect. So that's your initial concern here is, what's his blood pressure doing? So 120 over 80, that makes you feel a little bit more relaxed. You have some time to kind of think through this. And so with his blood pressure, we have, we have several options here. Okay. So we could consider beta blockers.

We could consider a calcium channel blocker, or if that's refractory, then we could consider some other anti arrhythmics such as amiodarone. All right. Why don't we dive in with beta blockers? Okay. Thanks. Okay, this always brings back some nightmares here for me because July 1st of my intern year, I was nervous and I

showed up to wards like at 4.

30 a. m. on my first day and my very first patient on wards had the exact same problem. New onset, eighth day with RBR, just recognized. I was like, oh gosh, this is real. You know, like, July 1st, here we go. Yeah. And of course my supervisor was in bed and I called him. My supervisor said, just give him five milligrams of ibuprofen per law at times five.

And he rolled over and said, see you in an hour. I was like, oh, okay. That sounds pretty straightforward. Okay. So I think that's a good thing for us to reach for. is IV metoprolol. IV metoprolol, it mostly affects the heart rate. It certainly can cause some hypotension, but perhaps not to to the degree that other beta blockers might, such as labetalol or carbetolol.

Okay, so metoprolol can be given intermittently, 5 milligrams every 5 minutes, up to about 3 doses total. Okay, but if you wanted to try something acutely, try to see if that was slowing you down, that's something that you could consider. Now again, you're going to want to get your labs back and make sure there's not something else provoking this.

Okay, is this AFib? Because he has pericardial effusion. Is it AFib

because his hemoglobin's gone from 10 to 6? You know, in that case, perhaps some of it's compensatory and he has a compensatory tachycardia. And so you always want to be questioning that in the back of your mind. Is that, am I going to make his hemodynamics worse by giving?

Yeah, always need to rule out other causes of AFib in the post operative patient. Electrolytes is a big one. For sure. Generally, the cardiology recommendation is always to keep the potassium above 4, keep the magnesium above 2. That's pretty much in any consult note that you're ever going to see, and there's a lot of truth to that.

Certainly, electrolyte abnormalities can make AFib more difficult to control and can also provoke cataract. We mentioned a little bit about diltiazem already. Um, as a hospitalist, I love diltiazem drips. Um, mostly because, uh, you tell the nursing staff, keep titrating up on the diltiazem until that heart rate comes down.

Yeah, and you can set some parameters and order it, and generally, usually it works. Okay, again, remember, make sure that there's no heart

failure, if you reduce the EF, make sure there's, uh, this patient's blood pressure is going to be able to tolerate that. Um, but that also would be a reasonable first step, is to start the diltiazem drip.

Okay, if you're refractory to either or both of those, it's reasonable you're reaching for IV amiodarone. Yeah, and IV amiodarone, you can start with a bolus. You can give a one time bolus of 150 milligrams, kind of IV push, uh, followed by an amiodarone drip. Probably at this point, you know, though, if you're still, it's the following morning, and your rates are still not greatly controlled, and you're trying beta blockers, they'll look at, or they'll say, I mean, so you're thinking about amiodarone drips.

You may be wanting to consider getting cardiology involved at this point and get seeking kind of expert consultation. Yeah. I think that's in the stable patient with AFib with RVR and reaching for that beta blocker right off the bat. That's great. If that fixes it, great job. You crushed it as the intern, and then I think the diltiazine as well as the amiodarone are good, are

good next steps for, for treatment for sure.

When are you considering electrocardioversion in this patient? Okay, so yeah, let's take this, let's take this similar situation, but now this patient's blood pressure is 90 over 60. And so, you're going to be maybe a little bit more hesitant to reach for a beta blocker or dilthiazemine situation. And then now the blood pressure is 80 over 50 and now it's 70 over 40.

Okay, so, you're going to want to go to the bedside and assess this patient. You're going to want to see, are they mentating well? You're going to want to, you know, Indications for who gets cardioverted is, quote unquote, your unstable tachyarrhythmias. Okay, so what makes someone unstable? Well, if they have, uh, altermental status, that counts.

If they have decompensated heart failure, that counts. If they're starting to develop angina because of their hypotension, that certainly counts. Okay, if, and if someone's falling off the sterling or the sterling curve and you're concerned they're going to be coding her shortly because their emo dynamics are, are, are plummeting like that, that's when you need to make some decisions quickly and get some help.

I think that would be appropriate to call a rapid response team or whatever your institution likes to use. Okay, because again, in that situation, you need to make some decisions quickly. You might need to sedate them. Patients will thank you if you, if they don't remember getting shocked. But our drugs that we typically use to sedate, like your IV midazolam and your, your IV fentanyl, uh, those are also going to cause hypotension.

And so if you need anesthesia there, you might need phlebotomy there to get some stat, uh, stat labs. You're going to want to get kind of your code cart there. You're going to want to get your, obviously your monitors on there and get the stickers on them in case you're, you're actually going to need to successfully cardiovert them.

Okay, so this is kind of a scary situation. You want to act though because you're want to, you know, cardioversion in an unstable tachyarrhythmia is the treatment of choice. But in, in real life, I think you're going to want to get some help. You're going to want to, uh, perhaps call an RRT and get some other people there to help you make that decision.

Uh, you're going to be calling cardiology concurrently. Okay, but if you really need to shock someone, you, you need to shock someone and you're going to save

their life doing so. If they're starting to fall off like that. Another pearl that I might say there is that this is going to be a synchronized cardio version.

Okay, so what's different between unsynchronized or synchronized? Well, synchronized, you press and hold the button and the machine is looking for the OR. Okay. Uh, on the QRS, okay? Cause you're trying to match up the shock with the delivery on the QRS. Cause what you don't want to accidentally do is unsynchronize and you accidentally press the button.

When the heart is re polarizing on the T Wave. And if you accidentally shock on the T Wave, is you can actually provoke B Fib. And that's, of course, not good. Okay, so you're going to want to synchronize it. Uh, typically 200 joules, um, is kind of the, the settings that you're going to want to shock on. And then we talked about sedation and doing it though, if, if that patient truly is quote unquote unstable.

That's really good. You delivered your shock and they converted out and woke up and asked you what happened. So good job. You saved, you saved their life. I think a really critical pearl there too is loading the boat as that July, August

intern, getting more people on board to kind of come help assess the situation.

All hands on deck. You are an unstable patient like this is always the right move. So I love that. 100 percent Medicine is knowing what you do know, but it's also knowing what you don't know. And also being, being comfortable, being comfortable acknowledging that outside my comfort zone and I need some help is a good clinician.

So a hundred percent. I agree. Okay. Let's move on to our second case. So, okay. Dr. Anderson, you're once again, uh, teleported to this alternate reality or nightmare, you might call it, where you're a surgical hentai, um, curing now for a 75 year old female who just underwent an elective left sigmoidectomy for smoldering diverticulitis.

Okay. It's post op D3 now. You get Paige that she has also developed a new onset atrial fibrillation on the monitor. You see her, she's tachycardic into the 130s, but hemodynamically stable. Blood pressure is 120 over 80, and she's satting well on

oxygen. You once again get your EKG, which confirms AFib with RBR.

What other workup do you want to get here? Um, I think basic, uh, you're going to get some basic electrolytes here. This patient deserves, uh, CBC, CMP, uh, a magnesium and an EKG here pretty quickly. Um, I think you have some time to get some labs back and look at any other reversible causes that perhaps could provoke this.

So, you know, if you're cross covering, this comes up, you know, you're going to look at her eyes and nose. You're gonna see how much fluids has she gotten, has she been pounded with fluids, and perhaps that's leading to atrial stretch. You're gonna get your labs that we discussed, make sure she's not nearly anemic, but you have some time here.

You order your set of rainbow labs, uh, nothing really pipes up, you maybe give her 2 grams of mag for a little bit of hypomagnesium. Uh, you give her a dose of ibuprofen and she immediately converts to sinus rhythm. Congratulations. You rocked it. Right. So let's chat a little bit about atrial fibrillation, um, following routine

non cardiac surgery.

What are the common risk factors for atrial fibrillation after non cardiac surgeries? Okay. Very good. Okay. So again, this, uh, atrial fibrillation is the most common arrhythmia in the world. And the incidence increases with age, and so her being, her having 75 birthdays is of course, uh, going to be a risk factor here.

So surgery is a innately, uh, stressful event. And so there's certainly increased, kind of, catecholic, um, surge, there's increased, quote unquote, adrenaline. Perhaps it's pain. Um, perhaps it's, you know, just environments and they're delirious and they're not sleeping and they're getting poked Q6 hours and vitals Q4 hours and telemetry on and eyes and nose.

And it's so hard to sleep in the hospital. So the, the traditional risk factors for AFib is similar to what we've talked about. It's age, electrolyte abnormalities, it's increased catecholamines and sympathetic response. Atrial enlargement is a, is a huge one and on any routine TTE, if you start looking at the left atrial size, if their

left atrial size is more than 40 millimeters squared, that's, uh, the, that, that risk factor increases as the left atrial size increases.

I think a good thing to look at here in this case is going to be her weights and her Is and Os. Um, we chart intake pretty well and our nursing staff does a great job with that because, you know, what's typically Being given, especially in this case, you know, she had a diverticulitis, so perhaps she's going to be MPO.

And so all of her fluids that she's gotten, all of her medications that she's gotten IV, are going to be very accurate. What's not going to be accurate, generally, is outlet. Because she's going to have lots of insensible losses. Um, insensible losses is where you lose all of your water from your respiratory rate or your, your rest, your respirations or from your skin.

Perhaps she has an NG tube in. You know, some post op patients not for, but you know, they might have a chest tube in. And so, and, and then people are, you know, they, we don't necessarily track their output as well because perhaps they are incontinent or perhaps they're not able to make it to the

urinal, uh, in time or whatnot.

So in general, you have to, sometimes the eyes are accurate, but the nose are. underestimated. And so if you just glance at the eyes and nose, you're like, oh gosh, this person's plus four liters or plus six liters, plus eight liters. Yeah, that may or may not be true. And so I think it's reasonable that the better sense for where someone's volume status is, is their weight.

And if someone's dry weight and their weights have certainly been increasing, that's the first thing that the cardiologists are going to look at when they're, when they're getting consulted is how much volume overload is there. And remember, you know, one liter of normal saline has like three and a half grams of sodium in it, right?

And it's not uncommon for us to give patients two, three liters per day. And so they're puffy and they're swollen and, you know, that causes lots of left atrial stretch and stuff too and can just be another, um, nidus. for causing AFib. Uh, we always throw hyperthyroid in here. Not very common for Graves disease to provoke AFib.

That's always included in part of the workup here too, so, um, when you're getting your routine labs, I would throw that on

here. It's relatively low value, it's, it's not going to change management a ton, but that's the first thing the cardiologists are going to do here too, so you want to steal their thunder as much as you can, right?

How common would you say AFib is in this patient? How common is AFib? You know, it's very common. It's something, somewhere around 10 to 15 percent following non cardiac surgery. And that's true for kind of overall incidence. In life as well as somewhere in that, in that uh, range here, you're going to, you know, make sure that is her wound healing up well.

Is there any evidence of a anastomosis leak? Is there any evidence of infection? Does she need a CT abdomen? Is she bleeding? Does she need a repeat h and h to trend her hemoglobin? You're really trying to see if there, is there something else that's provoked this. No, I love that. I think when you are approaching the post op atrial fibrillation new onset patient, you really do have to keep a broad differential and consider other things that can be contributing infection, bleeding, electrolyte abnormalities, especially when you're thinking about giving a beta blocker in these settings.

Like what are the things that the beta blocker might

take away that compensatory mechanism? I think that's really good to highlight. Should this patient be started on anticoagulation, or when are you reaching for that anticoagulation in this lady with diverticulitis? Okay, so, this is a little bit trickier when you have nuanced AFib in a post operative patient because obviously this patient just had surgery.

And so, is this, when did this episode of AFib happen? If she was symptomatic and she was on tele, yeah, we know exactly when her AFib started. Okay, for a single episode, if it's lasting for less than 48 hours. Routinely, we don't recommend anticoagulation unless there's really high, very high risk features for thromboembolism, like they have a valve or they have mitral stenosis, something like that.

Okay. And if the AFib is lasting longer than 48 hours, well, then that's usually where you're going to use your TADS MAS score to calculate the affirmative stroke risk. There's certainly some great calculators out there to help us stratify patient's risk. Okay, when we're anticoagulating patients for AFib, why are we doing that?

Okay. Well, we're trying to prevent clot. We're

trying to prevent stroke. And so generally the Scoring system or tool that's used the most is the CHADS VASc score and that's a reasonable first place to start to look at her risk and see what her CHADS VASc score because that's gonna give you a Gestalt for what her annual stroke risk is gonna be but she I think she was female She's 75 two points for her age and one point for fetal.

So she's already at 3. And, you know, if she has any history of hypertension, which is very common in 75, you know, she's already 4. Okay, so in general, if your CHAZ VASc score is above 3 for males and above 2 for females, then anticoagulation is almost always going to be recommended at some points. And even if your CHA2DS2 VASc is a 1 in males and a 2 in females, then usually in that case the benefits still outweigh the risks and generally it's still recommended.

You have to remember though that this is your annual risk of having a stroke. Okay, so your CHA2DS2 or 4. You know, that's going to come out to an annual risk around 4, 5, 6 percent. Somewhere in that range.

And so, what's your daily risk of stroke? Well, it's going to be 4 percent or 5 percent divided by 365.

So her daily risk of stroke is actually 000 something, right? It's going to be relatively low. Um, and so, but we, we need to keep this in mind because, you know, she just had surgery and certainly starting her on a Pixaban or a, a Novoloril and I like that. Certainly we have to weigh the benefits and the risks.

And then the key here is talking with the surgeons and talking with their comforts about her hemostasis. Okay. Thanks. And, you know, determining the risks of starting an anticoagulation at that point versus the benefits. Generally, after 48 hours, you know, she's supposed to update two or three, depending on the surgery and depending on how the surgery went.

Most of the time, that's probably going to be about the range where it's going to be considered safe to start that. But again, that needs to be a personalized conversation with the surgeon and the patient's risk. Yeah, I feel like anticoagulation post operatively is always a hot topic. I've always find it very hard to figure out when and when not to start it, but I think

it, it's hard because it is really that collaborative effort and you really do have to look at each patient, their risk and their benefits to going through it and kind of talking about that with internal medicine, surgery, the patient.

All of that is, is critical, so. The other scoring system to consider here is something called a HAZ BLED score, H A S B L E D. And again, that's, that's a way for you to objectively quantify what's going to be their bleeding risk. Do they have history of peptical disease? Do they have history of previous GI bleeds?

Are they on NSAIDs? And so that will let you weigh the risks and the benefits comparing their CHA2DS2 VASc score to their HASFLED score. Alright, so she did really good. That was her only episode while she was in hospital. What are you recommending on discharge? The nomenclature's kind of changed through the years and so it, historically, we maybe would have called this lone AFib or a provoked AFib.

Something that happens kind of one time and then it resolves and perhaps there was inciting events and maybe it was the surgery or the stress or hypokalemia or whatever. And so, kind of your, your gestalt is like, one little is

only one time, and she's better now. But, like we talked about, her risk going forward of having future episodes of AFib in the next five years is somewhere between 50%.

And that's what really kills people is, especially if they're not terribly symptomatic, is if you have a cold AFib and patients aren't well. Rela. I said they have that. That certainly increases your risk of stroke, and generally stroke from atrial fibrillation, it's clot from the left atrial appendage, right?

And so these are generally big clot. That clot when it breaks off, it tends to cause big MCAA, middle cerebral artery territory stroke, and so these are generally devastating strokes causing hemiparesis. So we really need to risk stratify her and try to decide if this is gonna be a recurrent thing that you need to continue to be monitoring for.

So let's take some examples here. Okay. In general, at this point, we need to decide, A, if she terminated and she's asymptomatic, do we need to consider some kind of longer term Holter monitor as an outpatient to see if she has recurrence? But it would be reasonable to consider bringing these patients for a

coltafib as an outpatient, especially the patients that are less symptomatic.

It's helpful when patients have symptoms and they can tell you. Man, right then and there, I knew I was having palpitations and fluttering in my chest, and I knew something was going on. That's only a subset of patients though, that's probably only 50 or 60 of patients. Symptoms? A good 30 or 40 percent of patients that have AFib are totally asymptomatic.

You ask them, do you have fatigue, shortness of breath, do you have exercise intolerance, they say. Doc, I had no idea that I was even in NATIB until someone told me. That's a population that's at, uh, perhaps higher risk of having complications because they're not, uh, aware of it, and then if they're not aware of it, then certainly they may or may not be anticoagulated at that point, and then they can perhaps be at higher risk of stroke.

This is maybe another whole topic in itself, but we could talk about rhythm control versus rate control. Yeah. And, uh, what do we do in this situation? Not to get super nerdy, but I mean, we're on a We're on a podcast. Get nerdy. Get nerdy. Cool. So, you know, the early trials in like the

early 2000s, like the big affirm trial that's often quoted, that was the, uh, trial that looked at, you know, was there a benefit between rate control versus rhythm?

And in general, the results of that study were Not significant. And so at that point, there wasn't a significant difference in mortality was the conclusions of the study comparing rate control versus rhythm control. And so that's been, that was the mantra for a long time until more recent studies have come out here.

Um, especially in the last, uh, couple of years where, um, the most recent study, I think this was published here last year, was called the AF NETWAR trial. Okay. And so in this trial, they randomized like 2, 800 patients with Early onset AFib, this was diagnosed less than a year, um, and they compared early rhythm control strategies with the control arm, which is typically rate control strategies.

And in these patients, what they found was early intervention basically lowered MACE. MACE is Major Adverse Cardiac Events. And so, there's a 25 percent reduction in the combined endpoint of

mortality. stroke, and hospitalizations due to heart failure, uh, or from acute coronary syndrome. And so this has really been a landmark trial that's pushed more the guidelines rate and management more towards early rhythm control strategies rather than rate control strategies.

So generally, the patients that tend to benefit more from a rhythm control, um, selection is the patients that A, tend to be more symptomatic. They have more fatigue. Remember, your atrial kick contributes 5 or 10 percent to your reduction fraction. And so when patients lose that, you know, they have more fatigue and tiredness and exercise intolerance.

B, the patients that are typically younger, the patients that are typically less comorbid tend to benefit more from an early rhythm control strategy. And that includes perhaps early referral to an EP cardiologist to consider cardiac ablation as now a grade one evidence for preventing long term atrial fibrillation and the lifelong burden of AFib.

The patients that maybe benefit more from a rate control strategy are the ones that typically are more

comorbid, more older, less symptomatic, and generally, if the patients don't care about their AFib, then we tend to not care as much about it either. And those are maybe the patients that you might, you know, acquire your rate, it's in beta block with goal heart rate, you get kind of less than a hundred and kind of send them on their way.

I think diving into the, the rhythm and the rate control is always important. I don't think you can have a conversation about AFib without going through some of those mutual trials. So that's awesome. Those were two really great cases. Why don't we highlight some take home points before leaving? What do you think the take home points today are, Dr.

Anderson? Okay, very good. Yeah, this is fun. Really appreciate the invite. Take home point number one is, at time zero, is try to figure out, is this patient stable or are they unstable? That's gonna be able to tell you. You have some time to think through this. Number two is get your basic labs, get your CBC, CMP, your magnesium, check the TSH, and you're gonna order a TTE.

Okay, if you're concerned about this is a post operative state, go lay eyes on that patient, go talk to the nurse, look at their eyes and nose, look at their weight, and Look at provoking factors,

see if there's anything that potentially can be reversed that you can fix. Uh, next, if they're stable, you have some time.

We talked about IV beta blockers. We talked about IV non dihydropyridine couts which kind of blockers have all failed reaching for amiodarone. Usually in those cases, you're going to be consulting cardiology and getting them involved at that point. If they're unstable, You're going to get some help quickly.

You're going to assess them. You're going to be considering, um, synchronized cardioversion and shocking them and saving their life. All right. Those are some great take home points. Thank you so much for joining us today. This was great. I feel like this is the team up that we need between internal medicine and surgery.

I love it. Thanks so much for the invite and, uh, yeah, happy to come back anytime. All right, everyone. Thanks for listening and don't forget to dominate the day.