Old inferior wall mi or Anterior fascicular block?

[tchristifulli]

What's the best way to figure out if the up down down leads 1,2,3 are a left anterior fascicular block or an old inferior wall MI?

 

[Anjel]

I think if you look at the entire twelve leave as a whole you will get a better idea. Look for pathological q waves and look at whether your t waves are positive or negative. If they are negative I think in your inferior leads, then that should give you a good start in differentiating the two.

If you only have the axis deviation, then I would call it a LAFB.

 

[Christopher]

What's the best way to figure out if the up down down leads 1,2,3 are a left anterior fascicular block or an old inferior wall MI?

With LAFB, Up/Down/Down isn't necessarily a rock solid way to identify it. I usually look for +I, -aVF, and -II which puts the axis between -30 and -90. You also need to have an rS in the inferior leads and small q's in I/aVL (this'll put the axis between -45 and -90).

Compare this to an "old inferior MI" where you'll have a Qr/QR in II, which gives it that negative appearance.

If you mix an "old inferior MI" and LAFB, you expect some combination of these two, giving rise to a QS, qrS, or QrS in II.

I'm not a fan of the "old XXX MI" stuff as it adds little outside of perhaps explaining aneurysmal ST changes.

 

[tchristifulli]

What is a Qr/QR?

 

[Christopher]

What is a Qr/QR?

Qr: Big Q-wave, little r-wave.

QR: Big Q-wave, big R-wave.

See here for other examples of QRS nomenclature:

 

[realmedics]

I had the same question a couple of months ago on a pt with a wacky ECG. I found a website (it's for doc students prepping for USMLE) that has some actual examples and criteria that helped me then and I bookmarked it. Here is the link:

learntheheart(dot)com/ecg-review/ecg-topic-reviews-and-criteria/left-anterior-fascicular-block-review/

Also, someone else said this as well, I learned the up/down/down method (thank you Dale Dubin) but that's not really as accurate as it should be. Here is the criteria (copy/paste from that link):

1.)Left axis deviation of at least -450
2.)The presence of a qR complex in lead I and a rS complex in lead III.
3.)Usually a rS complex in lead II and aVF as well (not always).

hope this helps

 

[Christopher]

I had the same question a couple of months ago on a pt with a wacky ECG. I found a website (it's for doc students prepping for USMLE) that has some actual examples and criteria that helped me then and I bookmarked it. Here is the link:

http://www.learntheheart.com/ecg-review/ecg-topic-reviews-and-criteria/left-anterior-fascicular-block-review/

<Grumble>, they've got a bizarre caption for that ECG, namely that you can't "diagnose" old inferior MI due to the "Q-waves in the inferior leads". Which are obviously not there.

Might I suggest instead The Alan E. Lindsay ECG Learning Center. Far better resource.

Also, someone else said this as well, I learned the up/down/down method (thank you Dale Dubin) but that's not really as accurate as it should be.

I wouldn't thank Dale, he's taught too many tricks and not enough actual electrocardiology.

 

[realmedics]

I wouldn't thank Dale, he's taught too many tricks and not enough actual electrocardiology.

You know, I read the forum post, shared the link, and then went back and re-read it... you're right, I not feeling it either. I like your link better. And touche re: Dubin.

 

[Christopher]

You know, I read the forum post, shared the link, and then went back and re-read it... you're right, I not feeling it either.

It is a bit distressing to note how many sites for doctors are completely lacking when it comes to the information presented! When you get into the niche/esoteric, it becomes even harder to figure it out unfortunately.

The good news is there are a number of high quality websites available.

 

[realmedics]

I know! I don't know about you, but I run into ER docs who aren't familiar with Sgarbossa criteria... I figured that would be mandatory for all docs, but one ER doc said "yeah if I see a LBBB I just consult." Must be nice lol.