Let us take a look at a typical LBBB pattern,
left bundle-branch block. Slow down for one second,
now before we go and dive into the EKG, which
at this point I would not recommend. I would
first pay attention to what kind of changes
you would expect to see or hear from the history
of the patient. For example, if you are to
do a cardiac ausculation with the left bundle-branch
block, this would mean that you have a delayed
conduction through the left bundle branch.
So, therefore, the first depolarization will
pass through the right bundle branch. If that
happens, then the pulmonic valves will closed
first prior to the aortic, thus you have a
paradoxical split. That would be the most
important aspect of left bundle branch block.
Now, when it comes to EKG, you have been given
a 12-lead ECG, well you are looking at your
V2, V3, V4 in which the QRS complex at this
point, in fact, has been widened, but it is
much more important that you pay attention
to the EKG upcoming with RBBB. Now, with right
bundle-branch block here, you are going to
have a delayed conduction passing through
your right bundle branch. So, you have a depolarization
passing through left bundle branch first
as you would have normally. However, now because
it takes the pulmonic valve to close a
little bit later, you are not going to have
a fixed split. You will have a wide split.
A fixed split would be upon inspiration, expiration
that the length in the span of your S2 between
A2 and P2 would not be changing and that would
be something like your atrial septal defect
as being the most common type of differential.
However, if you find a right bundle-branch
block, well you would have a widening, but
the size of the span between A2, P2 would change
between inspiration expiration, but it
would be widened in nature. Now, I want you
to pay attention on EKG now, based on
feedback, a 12-lead ECG and what has been
circled here? You notice rabbit ears is what
they are called. You have a RSR' pattern.
This I need you to be able to identify
on your EKG, on a 12 lead and with that type
of historym with the wide split, no doubt, your
diagnosis RBBB. This is the EKG at this point
that you pay attention to. Then when you get
a moment, go back to that electrocardiogram that
I showed you with LBBB, but as I said with
LBBB, you'd pay attention to the paradoxical
split. Is that clear? Let us now move on.
Now we move on to what's known as ventricular
tachyarryhthmia, your focus should be the
fact that the ventricles are involved. The
ventricles, which means that you are going
to find issues with which wave? QRS complex.
I want you to take a look at the bottom lead.
Also, what I am doing here with this entire
section of arrhythmia is I am trying to get
you into the habit of looking at all 12 leads.
Gone are the days where they are just going
to give you a simple rhythm or simple lead.
It just being one lead in which you need to
interpret that. Gone are those days. Even
with flutter, fibrillation any one of those,
there is a difference between, let us say
a licensing exam giving you one lead versus
giving you all 12. Because now all of a sudden
even you didn't know about your ADHD kicking
in. Dr. Raj, I didn't even know I had, but
they gave me 12 leads. I don't even know what to
look at because this is too much. That is
why you get conditioned. You take a look at
12 leads. Here we go. Don't panic and you
focus on things which you definitely know.
So we will take this opportunity to pay attention
to lead 1, 2 and 3. What does that mean to
you? Lead 1 left side, lead 2 you are looking
at 60 degrees approximately and once that
you want to pay attenion, you grouped together
based on myocardial infarction, we have done
this before. II, III, aVF, inferior portion.
Welcome to right coronary artery. Lead 1, aVL,
V5, V6 that would be the left circumflex, that
will be lateral side. If it is medial side
and then you are looking at a septal portion
looking at V1, V2, V3, V4 that will be intraventricular
down and then towards the apical and there
would be something like your left anterior
descending. You see the pattern. So each one
of these 12 leads that you are going through,
establish a pattern for yourself and I
would like you to move in a serpentine
nature, meaning lead 1, lead 2, lead 3 go up
to aVR, aVL, aVF go to V1, V2, V3 and I want
you to move in a snake-like manner with every
single 12-lead ECG that you get. Then at the
bottom that is the seperate strip. That is
a seperate lead that you pay attention to
because that would be the one that shows you
the pathology. Is that clear? This is how
you need to read ECGs for any licensing exam.
And by the way, you have cardiologists and experts that will
call that ECG and EKG, it's the same thing. In
Germany, it is EK cardio whereas it in English,
it is EC. Ultimately do not get confused on
that. It is the same darn test. Let us move on.