Your patient is pale and diaphoretic. Blood pressure is 70/50. Heart rate is 178. EKG shows atrial fibrillation… What are you going to do???
Yeah, yeah the Pavlovian ACLS response–You cardiovert. Wonderful, except it didn’t change a thing. Now what?
In this episode, I discuss the crashing atrial fibrillation patient.
Shock
If the patient is chronically in atrial fib, the shock rarely works. Your patient is unstable, so you decide to give it a shot. You might as well give yourself the best chance of success, so go right for 360 J on monophasic, or equivalently high on your biphasic. This will not cause more injury than lower joules (Heart 1998, 80:3 and Resuscitation 1998;36:193). PA is probably better than AA if you have pads. Make sure the synch is on.
You need to give your patient something to disguise the fact that you are electrocuting them. Yet you don’t want to drop their pressure. Ketamine is ok in disassociative dosing, but then your patient is loopy and you lose your mental status exam. Consider 5-7 mg of etomidate along with a pain dose of ketamine, 10-15 mg.
Screen for WPW
If you have a. fib with a wide QRS and a rate > 250-300, be scared, very scared. This is WPW and these patients just love to ruin your day by going into v. fib. Shock early, shock often, light them up.
Get the BP Up
So you made sure it’s not WPW and the cardioversion has failed, as it so often does in chronic a. fib. Now you need to raise the BP before anything else. Use push-dose phenylephrine. 50-200 mcg every minute or so until you get the blood pressure above a diastolic of 60; this will temporize the situation and make the patient’s heart more likely to slow down.
Though things look better, you have not really fixed the problem, you have just temporized.
Slow them them down
Give either amiodarone 150 mg bolus and then the drip (may repeat the bolus x 1)
Or
Use diltiazem, but not as a push. Drip it in at 2.5 mg/minute until HR < 100 or you get to 50 mg. See here for more.
Still not working?
- Consider magnesium
- Consider reshocking
- Consider cardiology consult
- Consider something else is going on
- Consider signing out to one of your colleagues and running away
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Hi, my name is Scott Weingart. 
{ 19 comments… read them below or add one }
I’m sure the cardiology consult will make everything better…
C
hee hee
Dear Scott,
Why don’t you use beta blokkers to slow them down?
No reason you can’t. I just have not found them to be as effective as dilt or amio.
I wouldn’t consider the patient’s home meds to contraindicate your choice in the ED. I think the way to go is to avoid giving two classes of meds IV. Procainamide is just built to lower the pt’s BP, so even with phenylephrine, I think you are better off avoiding it in a hypotensive patient. But if they are not shocking out, you can consider it.
Great talk about a scary topic.
In Australia, instead of phenylephrine, Metaraminol (Aramine) is a more popular drug, It is a fast acting peripheral vasocontrictor, loved by most anesthetist. In common practice, most doctors would mix one ampoule (2 mg) with Normal Saline to make up 20 ml and give one to two ml at a time. The bolus dose of Amiodaro0ne recommended is 3oomg followed by an infusion. I came across a similar case of crashing AF > 170 and hypotension 70/50 not long ago. To make the situation worse, he had infective COPD /type 2 respiratory failure with a high pCO2 of 85. Fortunately, the emergent cardioversion worked and he improved on NIV.
Paul,
Thanks for the info and the comment. It sounds like metaraminol is very similar to phenylephrine. So you folks start with the higher dose of amio right off the bat? Do you see a lot of hypotension from it?
scott
Dear Scott,
I ve read about the use of calcium as a pre treatment agent prior the use of calcium channel blockers ie ditialzem. They advocated us to give 5-10cc of calcium gluconate as to offset the hypotensive effect of the drug.
What do you think?
Calcium showed good effect as a pretreatment for verapamil. The data have not supported Ca pretreatment for dilt (J Emerg Med. 2004 May;26(4):395-400). However even though this study was an RCT, it was fairly useless b/c almost none of the patients got hypotensive in either group. However, calcium is an excellent inopressor in any patient, so I heartily agree that it would be a great thing to give in the patient above. Thanks for the comment.
Scott
Thanks for this podcast.
Can you do one on all remaining tachyarrythmias!
Regarding shock is it defibrillation or cardioversion in atrial fib with lo BP!.
I believe its cardioversion; the machine should still be able to sync on the R wave. I’ll add tachy rhythms to the future show list. thanks for listening.
Scott
nice lecture, pharmacist guy is learning alot, amio and diltiazem is very good for rate control, question why Phenyleph of all the pressors, u just want pure alpha effect and nothing to accelerate an already 250-300 HR?
exactly right. Phenyl will not make the heart rate higher and may actually lower it through vagal tone.
Hey Scott,
Great podcast. I heard the “gray hairs” in my dept talk about Dig, but it takes forever to kick in, right? Any role for it acutely, EVER?
Another obscure but cool-sounding strategy I have actually done a few times is to pretreat with CaGluconate then give small (5mg) Diltiazem boluses. Taught to me by said gray-hairs, this has little evidence. There was a small RCT in JEM 2004 that showed no difference in hypotension with Calcium vs. Placebo in RVR patients (J Emerg Med. 2004 May;26(4):395-400).
Have you done this?
Yup, CaGluc study is mentioned further up in this comment stream as well. Calcium pretreatment clearly works for verapamil, not as clear with dilt.
Dig takes hours as you mention so it generally won’t help in this scenario.
Thanks so much for commenting and listening!
Hi Scott. NICE talk on the Crashing AFib patient – which I’m only getting to in 2012 … (you first recorded this in 2010 … ).
As per above few comments – Calcium pre-treatment seems an option (realizing as you mention the data is with Verapamil) – but I believe YOUR emphasis in your podcast of using lower doses of IV Dilt given slower is the REAL key. Doing so has got to minimize the hypotensive effect. Clearly there is a balance one is seeking – which is to slow the rate of AFib (so as to increase diastolic filling time and improve hemodynamics) while not giving IV Dilt at too fast a rate such that BP is further lowered …. BP will come up IF you can improve LV filling and cardiac output – and the “art” is trying to balance the two …
As to Dig – my training says different than the textbooks (I completed my residency in 1975-1978) – so Dig is a drug that I’ve had a LOT of experience with during my earlier years of practice. I used it ALL the time in new-onset AFib. I fully agree with you – that IV Diltiazem is clearly preferred for initial new-onset rapid AFib (vs perhaps an IV beta-blocker in several select instances when increased sympathetic tone is felt to be operative) – but my point is that Dig will OFTEN begin to work within 15-20 minutes IF you bolus the patient (which is safe is the patient is not on the drug). Dig clearly has the advantage of being the ONLY agent among those used that increases inotropy (albeit by a limited amount), and doesn’t lower BP.
I realize in 2012 that the days of loading patients with IV Dig are pretty much GONE (and given unfamiliarity of currently-trained providers with the Drug, this may be best … ) – but my point is that this drug WILL often work much sooner than “in a few hours” if it is administered the way it used to commonly be used.
KEEP UP THE GREAT WORK ON EMCRIT!
Ken,
We have been having the same conversation about Dig on our tachy septic patients. What dose are you giving?
ROB – I’ll qualify my response by advising that I retired from my faculty slot in July, 2010 (after 30 years). I’m now “Emeritus” (which means I’m no longer practicing) – but the dosing I used for many years when practicing (and attending) regarding use of Digoxin is as follows:
- IF the patient has not previously been on the drug – consider IV loading (with 0.25-0.5 mg as the initial dose).
- May follow this with smaller IV increments (of 0.125-0.25 mg) every 2-6 hours, until a total loading dose (0f ~0.75-1.5mg) has been given over the first 24 hours. I’d use the lower range (~0.75 mg) for my loading dose with older patients, those with renal disease, those who are frail.
- In years past before my time, higher doses (of 0.5-0.75 mg) were given for initial IV loading. I always preferred use of lower boluses (as above) – which I felt was safer. I’d then be able to repeat smaller IV increments every 2-6 hours as above.
- The effect of Dig for a patient in rapid AFib may be synergistic with other agents (ie, with smaller doses of Dilt or beta-blockers) – it is a “1 + 1 = 5″ effect.
- Although full effect of Dig might not be for hours – I found rate slowing sometimes occurring within the first 15-30 minutes.
- The next day (after completion of IV loading) – the daily oral maintenance dose may be started. For most patients under ~60 yo (assuming they have normal renal function) – the daily oral maintenance dose = 0.25 mg/day.
- Lower doses should be used for older patients and/or those with renal impairment (0.125 mg PO – or even 0.125mg every other day).
- Dig is not totally absorbed when given PO. It is ~2/3 absorbed – so that an IV dose of 0.25 mg corresponds to a higher dose of the drug given orally.
- The “30-second” pharmacokinetics to be aware of is that the half-life of Dig is between 36 hours (in a healthy young adult) and ~5 days (in an older patient with renal failure). You can guesstimate what the half-life will be for your patient based on these 2 end points (Knowing the half-life is helpful if your patient gets toxic – since it gives you an idea for how long the drug will hang around).
Hope that helps.
Ooops – I meant to say Scott (Rob does the other great podcast show = ERCast)!
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