SVT vs Atrial Flutter

criticalHP, MSN, RN · May 21, 2009

One method I like to use is to slow the sweepspeed from 25 to 50 (don't forget to tell anyone else that may be monitoting at a central computer). This will allow you to identify features specific to SVT that can be buried in the fast rhythm.

Dinith88 · May 21, 2009

What methods can be used to differentiate between the two? I've been looking all over for a take home test I have and the strip (wish I could post) I put SVT but wondering if it may be Atrial Flutter with fast ventricular rate.
I'm thinking of putting possible Atrial Flutter with fast ventricular rate.
Thanks if anyone can help.

Technically, A-flutter is an SVT. By definition, any tachy-dysrhythmia that is being driven by a focus above the ventricles ('supra-ventricular') is an SVT. So...if you're seeing a fast flutter but cant really see the flutter-waves, you technically wont be wrong by calling it SVT. So...for the purposes of your test...if you can call your rhythm SVT...especially if you arent seeing any flutter-waves. If you're wrong, you can split hairs and complain and likely get the points...

Misty1 · May 21, 2009

Thanks. The question after the strip is How to determine AF from SVT. I've looked up in all my books and internet and can't find it. I'm sticking with SVT. and Thanks again

criticalHP, MSN, RN · May 21, 2009

If this is for a nursing exam it is a safe bet they want the super-anal-retentive nursing school answer. Therefore, yes it is techniqually all SVT. Atrial flutter is extremely regular whereas SVT can have even a slight variation in the R-R. March out your rhythm. If its for a test- this may be what they are looking for, but that's just my guess. In practice, however, if you are unsure you can call it SVT. Personally I would want to try to differentiate the two. Also, check an ECG (again, in practice). :twocents:

Misty1 · May 22, 2009

Thanks I didn't know the SVT was slightly irregular. I'd think it would be the other way around. Anyway I didn't know you could slow the sweep speed. That sounds like a good answer too.

Thank you again.

tri-rn · May 22, 2009

I think I'd go with the obvious....SVT has a p wave (although it can be buried in the QRS and therefore hard to see)....a-flutter has flutter waves but no normal p-wave....

Dinith88 · May 25, 2009

Thanks I didn't know the SVT was slightly irregular. I'd think it would be the other way around. Anyway I didn't know you could slow the sweep speed. That sounds like a good answer too.
Thank you again.

You're right. Flutters are often irregular ('variable' flutters) and can be very difficult to distinguish from A-fib when going fast.

They can also be very regular (2:1 flutter, etc.)

Classic SVT will be regular because the 'short-circuit' generating the rhythm doesn't change. (A-fibs/flutters are generated by more 'generalized irritability' in the atria).

Another thing to consider is that IF you see a p-wave in true SVT it wont be the same p-wave (or have the same morphology) as the p-waves seen when the patient's in sinus. This is because in true 'classic' SVT (more correctly 'AVNRT'-or AV-node re-entrant tachycardia) the rhythm is being driven by an irritable 'focus' outside of the SA-node. SA-node p-waves are 'normal' p-waves. P-waves (if apparent) in SVT/AVNRT will look (most of the time) different from sinus p-waves because they're not coming from the SA-node..

The thing to take from this is that all of these narrow, atrial tachy-dysrhthmias can be hard to differentiate...which is why 'SVT' is an umbrella term for all of them...rather than a specific diagnosis. Many nurses fail to recognize this.

Misty1 · May 26, 2009

ARGH!!!!!!!! Correct answer : Do an EKG. That was in my answer seems like sometimes we make things harder then they have to be.

Thanks to you all for your help

JF808Rn · Jun 14, 2009

yea. a 12 lead ekg is great. but if in case you don't have the time to wait around for one and if you're losing bp because of no preload. a quick way to check is with adenosine. done correctly you'll either see the flutter or stop the SVT... Hope this helps!

criticalHP, MSN, RN · Jun 20, 2009

yea. a 12 lead ekg is great. but if in case you don't have the time to wait around for one and if you're losing bp because of no preload. a quick way to check is with adenosine. done correctly you'll either see the flutter or stop the SVT... Hope this helps!

Good point-it the pt is crashing who cares what the fast rhythm is called. As long as you can differentiate between a wide QRS and a narrow QRS, you can treat the patient...

...Now, what about that nasty BBB? (I love to muck things up ) :lol2:

RNAEMTCC · Jul 6, 2009

Hm.

Well I don't entirely agree. I have seen irregular atrial flutter before.

And a rapid atrial fib/flutter (where they go in and out of both) can come across your screen at 200bpm looking like flutter.... or SVT.... sometimes you just love your patients.

I always slow the paper speed down (and then change it so you don't give the next nurse a heart attack) and then you can clearly see what you are looking at!

as usual, the best is an EKG, or a trial dose of adenosine (it's kinda a diagnostic medication) that i've seen some docs use to slow it down long enough to see whats going on... of course it's acls, so depending on the hospital a decompensating patient will get it without an order anyhow. .... if not for that pesky "prolonged asystole" they warn about on the box it's a great drug.