Today, I review and embed CriticalCareNow‘s How Do You Manage Unstable Atrial Fibrillation in Emergency Medicine and Critical Care?
All that follows is from the above resource.
May 21, 2023 ResusX:PodcastIn this video, Sara Crager discusses the management of Unstable A-Fib (Atrial Fibrillation). She highlights the importance of distinguishing between primary and secondary causes of instability before considering immediate cardioversion. Sara emphasizes that not all patients with A-Fib and low blood pressure require immediate intervention. Factors such as fluid status, electrolyte levels, and sympathetic activity should be evaluated to determine the underlying cause of instability. Sara advocates for a comprehensive approach that goes beyond the choice between beta blockers and calcium channel blockers. She introduces seven key questions to guide the management of Unstable A-Fib, including primary versus secondary causes, rate versus rhythm issues, the necessity of immediate cardioversion, electrolyte correction, fluid status assessment, and the use of appropriate medications. Sara suggests considering Amiodarone as a go-to option for rate and rhythm control in unstable A-Fib cases, while also addressing blood pressure support with medications like phenylephrine or vasopressin. Overall, this video provides valuable insights and strategies for effectively managing Unstable A-Fib.
00:04 Introduction to Unstable A-Fib
00:24 Understanding the Complexity of A-Fib
01:01 Broadening the Approach to A-Fib Treatment
01:47 Seven Questions to Guide A-Fib Treatment
01:59 Primary vs Secondary A-Fib
03:14 Case Study: Misdiagnosed A-Fib
04:03 Understanding the Role of Heart Rate in A-Fib
04:37 The Impact of Rhythm in A-Fib
07:06 The Role of Stress and Sympathetic Response in A-Fib
08:57
And so with him, I ended up doing something I do frequently with
8:53
A-Fib, which is a Precedex strip.
8:55
Because their sympathetic state matters.
8:57
Now, whether that means putting them on a Precedex strip, which I really
9:00
like doing because it makes you a little bradycardic sometimes it can
9:03
actually help you control the A-Fib.
9:05
It also just chills them out without depressing their airway reflexes.
9:08
If I put ’em on it early in, somebody who I think I may need to cardiovert,
9:11
often by the time I’ve decided whether or not I need to cardiovert them, they’re a
9:15
little chilled out on the Precedex strip.*
*Dosing Guidelines for Precedex®: Nonintubated Procedural Sedation and ICU Sedation [Link is to the PDF] from the American Association of Moderate Sedation Nurses, accessed 2/13/2025.
09:40 Importance of Correcting Electrolytes in A-Fib Treatment
Now, another reason that it might not work to cardiovert them is if
Mag
you haven’t fixed their electrolytes.
If their mag is 1, you can shock them as many times as you want to.
It’s not gonna work.
And so often you need to fix their electrolytes first.
And it’s hypo mag and hypo K that are gonna cause them to have
tachy dysrhythmias like A-Fib.
Now, I would usually just give them 2 grams of mag up front.
I don’t check the mag first because what’s the worst that could happen?
Do I really think that I’m gonna give 2 extra grams of mag and they’re
gonna stop breathing in front of me?
Probably not.
It takes a lot of mag.
We all remember our OB rotations and doing the mag checks, right?
Like your mag has to be pretty high.
And even if their creatinine is 9, if I give them 2 grams of mag and
their mag level goes up to 3 5, I still haven’t hurt my patient at all.
So, I don’t check the mag, I just give them 2 grams mag right off the bat.
If I’m giving them Potassium, which they often need, I’ll
target a Potassium of 4.4.
I’ll target a mag of 2.2 When I’m giving Potassium, I’ll give it PO
cause it’s just so much faster.
Get the liquid PO coz’ the caterer like the, like long-acting takes too long.
Correct the Potassium and the mag right off the bat coz’ it’s gonna be really
hard to fix the A-Fib if you don’t.
10:57 Addressing Fluid Status in A-Fib Patients
10:51
The other thing that it’s gonna make it really hard to fix the A-Fib if you
Fluid Status
10:54
don’t fix it, is their fluid status.
10:57
So, if they’re hypervolemic atrial stretch, yeah, the atria don’t love it.
11:02
When the atria get irritated, like when they’re stretched,
11:05
they like to go into A-Fib.
11:06
And so sometimes, for example, you’ll see this a lot, somebody with a history of
11:10
aortic stenosis, diastolic dysfunction, meaning they have a really steep
11:15
pressure volume curve in their heart.
11:17
So, like you give them a little bit of volume and it causes a really big increase
11:21
in pressure that gets then transmitted to the atria, stretches the atria
11:25
rapidly – those guys often go into A-Fib.
11:28
But it also turns out if they’re hypovolemic, you’ll
11:31
see this with secondary A-Fib.
11:33
If they’re going into A-Fib as a secondary response to hemorrhagic
11:37
shock, dehydration, septic shock, often they won’t get better
11:41
until you give them some fluid.
11:43
So, assessing your patient’s fluid status and trying to correct it
11:46
can be a really important thing.
11:47
And if you don’t do that, and that’s a big contributing factor,
11:51
it often won’t get better.11:56 Choosing the Right Drugs for A-Fib Treatment
11:53
Now, finally, drugs.
Drugs
11:56
When I’m talking about drugs for A-Fib, I talk about it really two categories.
12:00
One, drugs for hypotension.
12:03
That whole thing about we can’t possibly sedate them to cardiovert
12:05
them because they’re hypotensive.
12:07
That’s what phenylephrine.
12:09
Real easy.
12:10
I think, spend a little time with anesthesiologists and
12:13
you get real comfy with this.
12:14
Like you break it, you buy it mentality.
12:16
If I give my patient a drug that makes them hypotensive, I’m
12:19
allowed to give them another drug that makes them not hypotensive.
12:22
So phenylephrine, you can do pushes of a 100 mics, 150 mics, 200 mics, you
12:27
can just start a phenylephrine drip.
12:29
Often I’ll just get one at bedside.
12:31
So that, if I’m like, I may need to cardiovert this person, I’m gonna
12:34
start them on a little Precedex, I may give ’em a little fentanyl preparing
12:36
for cardioversion, have a little phenylephrine so I can say to the
12:39
nurse, if they get more hypotensive, don’t turn down the Precedex — turn
12:44
up the phenylephrine, if you need to.
12:46
So that’s as far as it goes for controlling hypotension.
12:49
Phenylephrine, you can use vasopressin.
12:51
Probably the best things to do.
12:53
Controlling rate rhythm.
12:55
I don’t use beta blockers or calcium channel blockers in a
12:58
patient who’s unstable A-Fib.
12:59
Why?
13:01
Because they’re unstable.
13:02
And I often don’t know why.
13:04
Like I may think I know that it’s a primary A-Fib and that
13:06
correcting the A-Fib will fix the hemodynamic instability.
13:10
But how sure am I about that?
13:11
Am I really sure?
13:13
Because if I’m not, let’s say my patient’s in septic shock or cardiogenic shock, I
13:18
give ’em a beta blocker right now they get really hypotensive or I give ’em a calcium
13:22
channel blocker and it’s even worse.
13:24
“Oh, don’t worry, now, I’ll just give them some norepinephrine.
13:26
Oh wait, I just blocked all their beta receptors”.
13:30
So, I don’t give beta blockers or calcium channel blockers.
13:32
What I like to do is Amiodarone.
13:34
Now, can Amiodarone cardiovert them?
13:36
Absolutely.
13:38
But if the patient is really that unstable after all of this, you’re probably
13:42
going towards cardioversion anyways.
13:44
And often Amio won’t necessarily cardiovert them.
13:46
It may just rate control them.
13:49
And in Unstable A-Fib, it may make them a little bit more hypotensive,
13:52
but the majority of the mechanism isn’t directly contradicting what
13:56
I would try and do with drugs like Norepi to support their blood pressure.
14:01
And so that’s why I’ll go to Amiodarone.
14:02
I’ll give 150 milligram bolus followed by a drip.
14:06
I’ll repeat another 150 milligram bolus.
14:08
But again, not as the only thing I’m doing as part of a bigger strategy.
14:13
So, in some my seven questions to unstable A-Fib are one, primary versus secondary.14:13 Conclusion: A Comprehensive Approach to Unstable A-Fib
14:13
So, in some my seven questions to unstable A-Fib are one, primary versus secondary.
14:20
Two, is it my rate or my rhythm that’s the problem?
14:23
Three, do I really need to shock right now?
14:26
Or do I need to fix all these other things and then try and
14:29
shock them if they don’t work?
14:31
Four, let me fix my electrolytes, my K and my mag.
14:34
Five, my fluid status.
14:35
Are they hypovolemic?
14:36
Hypervolemic?
14:37
Do I need to work on that?
14:39
Six, do they have a significantly overloaded sympathetic state?
14:43
Is their endogenous epi drip going nuts?
14:45
And lastly, my drugs to support their blood pressure as well as
14:50
to rate and rhythm control them.
14:52
My go-to for unstable A-Fib is generally Amiodarone.
14:55
If I have to use a beta blocker, I’ll go with esmolol but
14:58
Amiodarone is usually the way I go.
15:00
That’s it.
15:01
Thank you so much.Check out https://www.resusx.com for education on resuscitation
