Lifepak 12 and axis

[7887firemedic]

Love 12 lead interpretations, decided to further myself and dive into axis interp. My questions are: Lifepak gives 3 axis, which do i use or how do i use all 3? Second ? Is my understanding was axis goes from 0 to + or -90 and 180 with 30 degree increments, did a 12 today and got a t axis of 242? Pics of rhythm to follow

 

[VFlutter]

This probably explains it better than I can. Most people usually only care about QRS axis deviation. The computer will give an exact axis (kind of like NIBP vs manual)

http://lifeinthefastlane.com/ecg-library/basics/axis/

 

[7887firemedic]

Thanks! That helps with ? 1, now where did 242 come from, forum wont let me post a pic

 

[VFlutter]

Thanks! That helps with ? 1, now where did 242 come from, forum wont let me post a pic

It is the computer calculating the Axis to an exact number based off whatever algorithm it uses

 

[7887firemedic]

But if axis only goes to 180 as i understand, probably wrong, what does a number above that mean?

 

[NYMedic828]

But if axis only goes to 180 as i understand, probably wrong, what does a number above that mean?

I think it may have to do with whatever physiocontrol programs their monitor to do.

Phillips just spits out one QRS number.


Best way to know is calculate the axis on your own. It's really easy once you understand it. Find Toms blog.

 

[VFlutter]

But if axis only goes to 180 as i understand, probably wrong, what does a number above that mean?

Nvm, I wasn't paying attention to the number I thought you meant why it wasn't a 30 degree number. Maybe it was the T wave duration?

 

[NYMedic828]

Nvm, I wasn't paying attention to the number I thought you meant why it wasn't a 30 degree number. Maybe it was the T wave duration?

I assume he is referring to how it lists 3 numbers for the axis.

30-80-40 for example.

The answer to the question is the middle number (I think)

It lists P-QRS-T axis as far as I know.

 

[7887firemedic]

Thanks for the replies, i have been reading dubins method of up leads and down leads, seems like a fast way to check general axis, then the exact degree doesnt matter

 

[NYMedic828]

Thanks for the replies, i have been reading dubins method of up leads and down leads, seems like a fast way to check general axis, then the exact degree doesnt matter

Toms blog will give you a better explanation and understanding than dubins.

 

[7887firemedic]

I will check it out, thanks

 

[TomB]

Thanks! That helps with ? 1, now where did 242 come from, forum wont let me post a pic

On some machines a right axis deviation does not stop at 180 degrees but continues all the way to 270 degrees (in the right superior quadrant or "extreme axis" deviation). Which axis should you pay attention to? Mostly the QRS axis but I also look at the T axis. When there is 100 degrees or more difference between the QRS axis and T axis it's a "widened QRS/T angle" which means it's a general pattern of discordance so suspect LVH with strain, LBBB, hyperkalemia, ventricular rhythm, or paced rhythm (but probably not STEMI). So it's one of the quick ways you can rule out some of the more common STEMI mimics.

Tom

 

[7887firemedic]

Thanks Tom! Could you elaborate on dis/concordance, that is another confusing topic for me. Thanks

 

[Aprz]

Concordant T waves will be the same dirction as the last wave/deflection in the QRS complex e.g. you have a Rs complex, a concordant t wave would be negative. Discordant would be the opposite so an Rs complex with discordant T wave would be positive, it's going the opposite way as that last s wave. Size doesn't matter or if the overal complex is positive, isoelectric, or negative, all that matters is that last wave in the complex.

More example, qR complex, T wave would concordant with it if it's positive (cause the R wave is positive) and T wave would discordant if it's negative (cause the R wave is positive, T wave is negative, it's the opposite direction of the last wave in the qR complex).

 

[7887firemedic]

Got it, now what do i want to see concordance or discordance?

 

[TomB]

Discordance. But not too much (in LBBB and paced rhythm).

http://ems12lead.com/2010/12/excessive-discordance-as-a-marker-of-acute-stemi-in-lbbb/

 

[7887firemedic]

Thanks, so concordance would signify? MI?

 

[7887firemedic]

Nevermind, phone didnt show the link, thanks all!

 

[Craig Alan Evans]

 

[Craig Alan Evans]

It's actually the ST segment at the J point that should be discordant. A picture is worth 1000 words so here is 2000 words for ya.