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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{ 12 comments… read them below or add one }
I’m sure the cardiology consult will make everything better…
C
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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
A-fib, low bp, looks like crap, shock didn’t work. What now? Listen to EMCrit Podcast 20. http://su.pr/1aTmjS
This comment was originally posted on Twitter
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