What kind of changes that you are going to
find on your EKG. Well, we will get into that
here. Let us talk about transmural first.
If it is transmural, what kind of artery or
arteriole? It is going to be your artery and
it is undergoing permanent type of obstruction.
What are you going to find on your EKG? You
are going to find a type of change, which
is known as a STEMI, an ST-elevation myocardial
infarction, left anterior descending branch.
Take a look at where the occlusion is taking
place. What part of the heart is that? You
see that right there? That is the anteroseptal
right. So you have your interventricular septum
and then towards your apical. What leads would
these be? Actually the second time, but I
am walking you through all leads here, then
keep repeating myself. So we have the following.
We are supplying the, who is? The left anterior
descending is supplying the interventricular
septum, is it not? And so, therefore, it would
be V1, V2 and for exam purposes also understand
that you are going to supply the anteroapical.
What leads would those be? V3, V4 good. Welcome
to left anterior descending. Transmural, what
kind of infarction? ST elevation in which
leads? V1 through V4. I am hoping that you
have done your precordial leads and you know
how to place them. Next, permanent occlusion
of left circumflex
branch. Take a look at where you are here.
Once again, it is an artery. What kind of
myocardial infarction? STEMI. Next, what kind
of leads that you are looking at? What is over
here on your left lateral side? How about
V5, V6? What else might you find? Lead 1, which
augment the lead. Please do not say aVR. That
is aVL, isn't it? Okay. So those are places
that you do expect to find an ST elevation
if it is left circumflex. And then if it is
right coronary artery, where might you be
here? Well, this is your II, III, aVF? That
will be the inferior portion of the heart.
Let us move on. Let us take a look at nontransmural.
If it is nontransmural, then these are the
different types of issues that you are looking
at. We have transient/partial obstruction,
point number one, subendocardial infarction.
Global hypotension, what does that mean? It
means overall the blood pressure is decreasing
in your patient. Thus, you will find circumferential.
Look for that description. Why is it happening?
Overall the body. Let us say that there is
massive type of hypovolemia due to massive
hemorrhage. Is that global hypotension? Of
course, it is. What part of the heart is most
susceptible to hypoxia? It is the subendocardium,
but now it is circumferential. Small intramural,
these are microinfarcts. Now the two that
you want to pay attention to, for sure would be
the first and second one with subendocardial,
either you have a partial obstruction or you
have global with circumferential.
All, however, would be nontransmural.