00:01
Ready for step five?
We're going to look at the ST segment.
00:05
Now the ST segment is the early
repolarization of the heart's chambers.
00:10
So look at the isoelectric line.
00:13
Remember depolarization is
contract, repolarization is relax.
00:19
So we're looking at the ST segment,
we've gone through the P wave,
then the isoelectric line for a little delay, QRS
and now we're talking about the ST segment.
00:33
So this segment lets us know how the heart
has repolarized, it's the early part of that.
00:39
Let's remember the interval of time between the
ventricular depolarization and repolarization.
00:46
That's what's reflected as the ST segment.
00:48
And because during this amount of time,
there is no impulse activity in the heart,
the segment should be reflected in the
ECG strip as a flat isoelectric line.
00:58
Now, elevations and depressions of the ST
segment could be a sign of cardiac problems,
like myocardial ischemia.
01:06
Okay, I have a 12-lead here again,
because I just want to remind you,
if you see an elevated ST segment when you're
doing a regular ECG, lead II kind of strip,
then you know, the next step
will be to order a 12-lead ECG.
01:22
You want to take a look at that, because
they're going to want to look at the heart
in all different kinds of leads.
01:28
So why is everybody getting so excited
about that ST segment elevation?
because it's an indication that the patient
could be having a myocardial infarction.
01:38
You'll hear people call it a STEMI.
01:41
STEMI is not the news anyone wants to
get about themselves or their patient.
01:46
STEMI stands for ST-elevated myocardial
infarction, and NSTEMI would be a non-STEMI
or a non ST-elevated myocardial infarction.
02:00
So all you have to keep in mind for these
beginning stages of understanding ECG
is that if something looks odd with that ST segment
and it is elevated above that isoelectric line,
You need, to the next step you need
to call a physician, the practitioner,
we need to find out what is
best to do for this patient.