welcome to another MedCram lecture we're going to go over this EKG just like we
do in our EKG course atma crammed calm so the first thing that we want to do is
get the history and this happens to be a 78 year old Caucasian male found down in
a nursing home with a temperature of 85 degrees Fahrenheit so the first thing
that we want to do like we learn in the course is go over rate rhythm and axis
okay rate rhythm and axis so the first thing on rate is you can notice here
that there are QRS complexes and what you really want to do is look at the
rhythm strip which is down here and you'll notice here and here and at
various places along this rhythm strip our QRS complexes which are pretty
irregular which means it's going to be difficult for you to use the box method
of calculating the distance in time between each QRS complex so you know
when we're talking about these big boxes here how many boxes are there between
these QRS complexes and you know that the first box is going to be 300 the
second box is going to be 150 and the next one is going to be 100 but the
problem here is that these QRS complexes are irregularly spaced so whenever I
have something like this where we may be dealing with atrial fibrillation the way
I like to do it is look at a whole rhythm strip and make sure that we're
going at 25 millimeters per second which is the standard paper and all you do is
you just take the number of QRS complexes in one standard size EKG strip
and you multiply it by 6 and the reason why is it takes 10 seconds to do the
entire strip so you're seeing how many complexes are there in 10 seconds and of
course there's 60 seconds in a minute so let's go through it we've got 1 2 3 10
11 so 11 times 6 so our rate is 60 six okay well what about the rhythm so
look at the rhythm strip again and you'll notice in this situation that
there are really no P waves before these QRS complexes so I do believe because of
the irregularity and because of the lack of recognisable standard P waves that
we're dealing with atrial fibrillation okay finally axis now this is sometimes
where people get confused let's go ahead and review axis like we do in the course
so the best way that I can remember how to do axis is just draw a circle draw a
central hole and the way I remember this is to remember whenever you've got for
instance an inferior myocardial infarction you're always going to look
at the bottom of the heart with leads to three and AVF so two is going to be
generally pointing down three symmetrically on the other side and then
a VF okay now of course you can extend those back because it's exactly the same
axis it's just the the negative aspect of it now we know that lead one goes off
in this direction so that's Roman numeral one and so
really all you have to do is fill in the other ones and so that's gonna be a V R
because that's the right side of the body and here that's gonna be a V L so
we should have six leads okay we've got one two three four five and six and each
of these is spaced out by thirty degrees okay so we're going to go through this
looking at the EKG strip so the first thing that I like to do in terms of
trying to figure out what the axis is is I always do the 90-degree coordinates
one in AVF now they're both positive here and here and as you recall the axis
is always measured from this and it's always measured positive this way
always measure negative this way so if we're positive and positive we've got to
be in this quadrant so let's take a look at our EKG okay so here we're going to
look at lead 1 which is right here and we're going to look at a VF which is
down here notice that in a VF and in one we both have a positive QRS complex so
what does that mean that means that our axis is going to be somewhere in this
quadrant which is normal that's where it should be but let's refine it even more
is it closer to lead - is it closer to the negative of AVR exactly where is it
that we're talking about well there's a another way of doing that and that is
looking at to see whether or not the amplitude of the QRS is higher in a VF
or two or if it is most negative in AVR that'll tell us where along here it is
or even in Roman numeral lead one so let's take a look so if we look at this
we can see that a VF seems to be the highest at around ten millimeters here
whereas Roman lead 2 is only about eight millimeters and if we look at a VR here
it's negative by about oh I would say about nine millimeters so the one that
it's highest to is a VF but remember Roman numeral lead one shows that it
actually is positive so it's not right on a VF it's got to be just off of it so
we would look at this and say that it's probably running right along here
somewhere in this range now if that's the case then that would mean that it's
perpendicular closest lead which in this case would be a VL should have the
isoelectric big why because it's perpendicular to the maximum amplitude
so when we go back and look at the EKG let's look at a VL and see if that one
has the lowest amplitude and of course when we look at it we can
see very clearly out of all of these limb leads AVL has the lowest amplitude
and that confirms that our axis is around 60 to 67 degrees which would be
right around where we predicted it would be okay so that's how you can do axis
there's actually several ways of doing that
so we'll just round it off and say 60 degrees okay so we've got rate rythm
axis now are there any kind of funny ST segment changes and the answer is yes
you can see here it kind of notching now there's several names for this notching
it's known as the J wave or even called an Osborn wave the reason why it's
called an oz born wave is because it was discovered in 1953 by a guy named Osborn
who was doing research in something very interesting it was research in
hypothermia and that kind of gives away why you might see a J wave or Osborn
wave now first of all it's known as many other things that's known as a camel
hump sign a late Delta wave a hat hook Junction a hypo thermic wave a ke wave
and H wave so there's a lot of different names for it but you'll see J wave and
Osborne waves the most and it can be related to a decrease in temperature of
the patient so this is pretty classic for this you might see this on boards
and typically when the patient has a temperature of less than 90 degrees
Fahrenheit as we said this patient actually was 85 degrees Fahrenheit so it
certainly would make sense but you can also see it in hypercalcemia you can see
it in brain injury and you could also see it in vasospasm angina and you could
also see it in v-fib but the one that you ought to know about and remember is
decrease temperature Osborne wave J wave and that's what it looks like
let's take another good look at some of these examples but first let's look at a
close-up basically it is a rebounding after the J
point of this hump that comes after the R wave and again here's another example
typically you'll see it in two precordial leads so there is a J wave
and again remember this in patients who are hypothermia okay well we've gone
through another EKG join us over at make cram comm for our EKG course because the
more EKGs you do the better you get thanks for joining us