00:01
So, we've done step one.
00:02
We've looked at the heart rate
and the rhythm.
00:05
I reviewed
what's going on in the heart
with all the different
parts of the ECG?
Now, we're going to look at,
how to analyze the P wave?
What's that?
Okay, so what does it mean
the P wave?
That's right,
atrial depolarization.
00:20
See, you can do this.
It takes some effort.
00:23
But the more you keep
answering questions,
you're going to make
those connections
between the neurons in your brain,
make those super strong,
and that's what you want.
00:32
So let's analyze the P wave.
00:34
We know the P wave is the
depolarization of the atrium.
00:38
Keep in mind,
it's both the left and the right.
00:41
Now, sometimes
I was just talking about
on the right side of the heart,
but it's happening
at the same time.
00:46
So, look at our picture.
00:47
You can see that we have that
reaching way over to the left side,
and right there on the right side.
00:54
Okay, so they both are going
at the same time.
00:58
Both of those
atrium and ventricles.
01:00
So in the cardiac cycle,
the P wave represents
the depolarization of the atria.
01:06
That means they undergo
contraction.
01:08
So have you thought about,
why if the heart has two atria,
there's only one single waveform
for the P wave?
Well, both the left and right atria
depolarize, at about the same time,
and so they're kind of just
on top of each other.
01:22
That's why you only see one P wave
or a single wave on the strip.
01:28
So step two is
analyzing the P waves.
01:32
But I want to explain what I mean
when I say that.
01:34
There are four important
questions that you should ask
when you're analyzing the P waves.
01:39
Number one,
first of all, are they there?
So are the P waves present?
And so looking at this strip,
we put a blue box
over each one of the P wave.
01:50
So yeah, we've got P waves.
They are present.
01:54
Number two,
is there one P wave for each QRS?
I look at each one of the beats
on a six second strip.
02:02
P wave QRS, P wave QRS,
P wave QRS, P wave QRS,
P wave QRS, P wave QRS,
P wave Q...
02:09
Yeah, there is a P wave
for each QRS.
02:13
Now, are the P wave smooth,
rounded, and upright?
Yep.
02:18
Yep.
02:20
Yep.
02:21
Yep.
02:22
Yep.
02:23
Yep.
02:24
Yeah, we're good.
So far, they're present.
02:27
I have one P wave for each QRS,
the waves are smooth,
rounded, and upright,
and do all the P waves
look the same?
Yeah, they do.
02:40
This tells me,
things are going well, right.
02:44
This is what I'm looking for.
02:46
Now, I'll talk to you
in a little bit
about what it means
when that P wave
doesn't meet
all four of these criteria.
02:53
So when you're analyzing
the P wave,
if the answer is no
to one of these four questions,
you'll tell us more about
what could be going on in the heart.
03:03
Because look at this.
03:05
Now, in normal sinus rhythm,
you see how that P wave
is rounded peak,
just like we thought it would be.
But got some challenges going on.
03:16
See how weird
these other P waves look.
03:18
Now, at this point,
I don't want you to memorize this.
03:22
I just want you to know,
this is why we analyze a P wave
and we ask those four questions.
03:28
Because look at that second P wave
that might show us
right atrial enlargement.
03:34
Look at the next P wave,
the third one,
right there on the bottom.
03:37
See it.
03:38
That could be
it's got that little notch in it.
03:41
That could be
left atrial enlargement.
03:43
So, I don't want to go
into detail on this.
03:46
I want to just to explain to you
why is it so important
that we answer
those four questions
about P waves?
Because if they
don't look like that,
we're going to need to answer
some more questions
in more advanced ECG monitoring.
03:59
But for now, if you can answer
those four questions,
right now we have a
pretty normal rhythm.
04:04
We're good.
04:06
Now, here's a really unusual
example of when the P waves
don't look normal.
04:11
We call it a junctional rhythm.
04:13
Now, if you look at that strip,
where do you see the P waves?
Well, they're not there.
04:19
Because a junctional rhythm
the impulse originates
at the AV node
Know it has some retro grade
and antegrade direction.
04:26
But that's why you don't see
the normal P wave.
04:29
Sometimes the P wave
will be inverted.
04:31
And it may be under or after
the QRS complex
because the heart rate
is so slow.
04:36
So it's there.
04:38
It's just not in the typical place
that we expect it to be,
and it likely doesn't look normal.
04:44
So this patient needs
further assessment.
04:47
When you have these
abnormal P waves
they happen with enlarged atria
or when they come from
outside the SA node,
this needs to be evaluated
by the healthcare provider
to determine the extent
of follow up care
that might be necessary.