00:01
Hello.
00:02
Now we're going to talk about
acute coronary syndromes
a very common and important problem
in the emergency department.
00:11
So coronary syndrome is
actually very common.
00:13
In the United States, there are more
than three quarters of a million cases
of coronary syndromes each year.
00:20
The mean age is 68 years of age
but the interquartile
ratio goes from 56 to 79.
00:25
So this is really
a disease process
that affects pretty
much all adults.
00:30
There is a male to
female predominance.
00:32
So for every 10 patients
with coronary syndromes
six will be men
for will be women.
00:40
And 70% of coronary syndromes
are non-st segment elevations,
meaning these are not acute MI's
that are getting
rushed to the cath lab.
00:49
These are patients who
have more subtle findings
or in some cases even no
findings on their initial ECGs.
00:55
So recent trends
when you look at the epidemiology
of coronary syndromes
shows that we're actually
seeing fewer and fewer
massive ST segment
elevation events
and more and more non-st
segment elevation events.
01:10
So again, we're not seeing
big acute coronary occlusions.
01:13
We're seeing more
subtle ischemia.
01:16
Short-term mortality is
stable across the board
so there's not really been any change
in the likelihood of people dying from
coronary syndromes
in the short term,
but fortunately long-term survival
is improving and that's largely
due to improvements in diagnosis
short-term and long-term
management for these patients.
01:36
So what is a coronary syndrome?
Very simply is an
acute coronary syndrome
is any new condition
that leads to inadequate
myocardial perfusion
relative to demand.
01:49
So if the heart's not
getting enough oxygen,
it's not getting as much
as it needs metabolically.
01:54
That is a coronary syndrome.
01:56
Now most coronary syndromes
start with chest pain.
01:59
However,
among patients with chest pain
the vast majority are actually not
having acute coronary syndromes
although there is of course a
significant overlap in the middle.
02:10
Among patients with
coronary syndromes.
02:12
There's a continuum of disease.
02:14
So patients may
have unstable angina
patients may have non-st segment
elevation myocardial infarctions
or patients may have ST segment
elevation myocardial infarctions.
02:27
So this is a continuum
of disease acuity
and there's different management depending
on the patient's clinical presentation.
02:36
When we look at unstable angina.
02:39
We're generally talking about
ischemic chest pain that occurs
either while the patients at rest
or with levels of exertion that
they're normally able to tolerate
I go out for a two mile walk
every day Nd usually I'm fine
abut in the past week, I'm getting chest
tightness or getting short of breath
within half a mile
and I have to sit down
that's an example of
impaired exercise tolerance.
03:03
For these patients when they come
see you in the emergency department.
03:06
They'll often have
no ECG findings
or their ECG findings
will be very nonspecific
and their lab abnormalities
will be negligible as well.
03:15
So these patients are not going
to typically present to you
with elevated troponins.
03:19
By contrast, patients who have
NSTEMIs or non-st elevation MI's
these are patients who can have
ischemic chest pain in any setting,
it might only be with exertion.
03:30
It might be at rest.
03:33
When they present they
will typically have
some degree of EKG changes
although a small
percent will have none.
03:39
However, those changes are going to
usually be st-segment depressions.
03:44
They're not going to be elevations
because that's a different type of infarct
and these patients are really
characterized by their elevated troponin.
03:51
So they come in with chest pain.
03:53
They have EKGs that are not
definitively
diagnostic of an MI,
but they show that they
have elevated troponins.
04:00
And that's evidence of
coronary infarction,
that's our NSTEMI patient.
04:05
And then lastly we have our
STEMI patients or patients with
ST elevation MI size.
04:10
And these patients again,
have chest pain that
might occur at rest.
04:14
It might occur during exertion,
but it's typically
a single acute event
and they're going to
come in with the classic
ST segment elevation that we
all learned in medical school
characterized acute
myocardial infarctions.
04:29
Now for these patients, they will
typically have elevated troponin,
but we won't even see that
in the emergency department
because patients with
STEMIs get emergent
definitive treatment for
their coronary disease
and they're not going to be hanging
around the ED for long enough
for us to see there
troponin is go up.
04:45
So that's going to be more
of an inpatient finding
and we're going to make
that diagnosis based on
EKG findings alone while they're
in the emergency department.
04:56
So when we see patients
with chest pain
and we suspect
coronary syndromes,
we always want to get a
rapid history and physical.
05:03
We want to know what was
happening when the pain started.
05:06
How did it start?
What did it feel like,
what are all the circumstances
surrounding this presentation?
And we want to get an ECG and we
want to do that very very quickly
typically within 10 minutes of the
time the patient arrives to the door.
05:20
If they're having a STEMI
then they need to get a
immediate definitive management.
05:26
So a STEMI tells you
that the patient has
complete occlusion
of a coronary artery
that is causing transmural
full thickness infarct
of part of their heart.
05:35
That's bad right,
time is myocardium.
05:38
So these patients are going
to go directly to cardiology
and get definitive management,
which we'll talk about in a minute.
05:45
If they're not having STEMIs,
we have a little bit more
time to think about them
and we'll go through
that algorithm second.
05:51
So here's a perfect
example of a STEMI,
you can see see in all
the anterolateral leads.
05:57
So V2 V3 V4 V5 V6
also leads one and AVL
you see tombstones, right?
These are the classic
convex ST segment elevation
that we all learned
about in medical school.
06:11
This is a STEMI.
06:14
So once again isoelectric baseline,
which is highlighted in black,
that's the PR segment and
the TP segment, right?
That's where the isoelectric
base line is supposed to be.
06:25
If you look at the ST-Segment 1
millimeter after the QRS complex,
which is by convention
where we measure it,
you can see with
the new highlight
that ST-segment is
way up in the air
above that Isoelectric
base line.
06:40
So it's higher
than it should be.
06:41
Isoelectric baseline,
st-segment up above it,
that's an ST segment elevation.
06:47
And again on this ECG,
we're seeing it not just in
the leads that are outlined
but in several leads.
06:53
In order to diagnose
somebody with a STEMI,
I mentioned before we're using the
ECG is our primary diagnostic tool.
07:00
So the patient of course
has to have a history
that's compatible with
ischemic chest pain
and they have to have ST
segment elevation in two or more
anatomically contiguous leads.
07:10
So in the anterior
leads which are
the two through V4,
the lateral leads which are
V5 and V6 and one in AVL
or the inferior leads which
are two three and AVF.
07:23
They have to have ST segment
elevations two or more
anatomically contiguous leads.
07:28
We're typically looking
for two millimeters in men
and 1.5 millimeters in women
in especially V2 and V3
because that's a common place
where you see non pathologic
ST segment or J point elevation.
07:42
In all the other leads,
we're looking for one millimeter
of ST segment elevation.
07:47
So when you're measuring
your ST segment,
you want to make
sure that you know
1. what your Anatomy is,
so you want to know which leads go with
which anatomical piece of the heart
and again anterior is
going to be V2 V3 V4.
08:01
Lateral is going to be V5 V6,
1 and AVL
and inferior is going
to be 2/3 and AVF.
08:10
So we want to know if they're
anatomically contiguous
and we want to know how high
the ST segment is elevated
relative to the standard
for that particular lead.
08:21
The second criterion for ST
segment elevation diagnosis
is ST segment
depression in V1 and V2,
and very simply that represents
posterior infarction.
08:32
And if you think about it,
we always put ECG leads
on the anterior
part of the chest.
08:37
But if you're infarcting
the back of your heart
that image on your surface
ECG is going to be inverted.
08:45
It's going to look upside
down and backwards.
08:48
So ST-segment elevation zones that
are occurring in the back of the heart
will look like depressions
when they're measured from
the front of the body.
08:57
That's why V1 and V2 are special
and ST segment depressions and
those leads are considered to be
ST-elevations for the
posterior of the heart.
09:07
The final criterion is a new
left bundle branch block,
which of course this
ECG does not demonstrate
but if the patient has new development
of QRS widening and a left bundle pattern
that is also highly suggestive
of a myocardial infarction.
09:21
So once the patient
meets those criteria,
what are we going
to do about it?
Well, first and foremost,
we are very rapidly going to
revascularize their
coronary arteries.
09:32
So again ST-segment
elevation means
you've got complete
occlusion of an artery
that is causing transmural
infarction of the heart
that is not good.
09:42
We need to get that artery open
back up and we need to save
whatever myocardial tissue
we can that's distal to it.
09:49
The best way to
accomplish that by far is
with percutaneous coronary
intervention or PCI
that refers to going
to the cath lab
performing angiography inserting
stents to hold the coronaries open.
10:04
The other option that's
available is thrombolysis
that involves giving a
clot-busting drug systemically.
10:10
However, it's not as effective
as PCI and it's not as safe.
10:13
So any time you have the
option of Performing PCI,
that's always going to be
the preferred technique
provided you can do
in a timely manner.
10:22
So the goal door-to-balloon time
for PCI should be under 90 minutes.
10:27
If you're over 90 minutes,
you don't think you're going
to be able to get the patient
to a center where they can perform
PCI in a 90 minute timeframe.
10:36
Unfortunately that
piece of heart
that's distal to that included
coronary artery is going to die.
10:42
So you need to go to plan B,
which is going to be again
systemic thrombolysis.
10:47
Now, we're using that
less and less and less
in modern times because
there's more and more centers
that are capable
of Performing PCI.
10:55
But if you happen to be practicing
in a limited resource setting
thrombolysis might be
your only option to save
the threatened piece of
the patient's myocardium.
11:05
So it is something we should be
aware of in our armamentarium,
even though we prefer PCI.
11:12
In addition to revascularisation
while you're waiting for your
patient to go to the cath lab
you want to make sure that you
optimize their medical management.
11:20
So we're going to give
them antiplatelet therapy
in the form of aspirin
and an antiplatelet agent such
as Clopidogrel or Ticagrelor.
11:28
We can also think about
an oral beta blocker
if there's no contraindication
to doing that.
11:33
Now beta blockers in the acute
setting are not nearly as important
as they are long-term following
the myocardial infarction.
11:40
But for patients who have significant
hypertension or tachycardia on arrival,
it might decrease strain
on the heart and ultimately
improve their outcome so
you can think about it.
11:49
Although it's not
mandatory to give up front.
11:53
We do definitely want to
provide anticoagulation
usually in the form of
unfractionated Heparin
for patients who are going
to be going to the cath lab
for the simple reason that
in the event they have
a bleeding complication.
12:05
We want to be able
to turn it off
and not have uncontrolled
anticoagulants.
12:10
Kicking around round in their
system preventing us from
being able to control
their bleeding.
12:16
And then lastly we want
to think about analgesia.
12:18
So typically either
nitroglycerin or morphine is used
if there's not a
contraindication.
12:23
Now morphine has been a little
bit controversial lately
because of some
studies that have
showed adverse outcomes
associated with morphine,
but it's still a reasonable thing
to think about for a patient
with chest pain that's
refractory to nitroglycerine
because we do want to alleviate
our patients suffering
in addition to giving them the
definitive treatment that they need.
12:42
Recently fentanyl
has replaced morphine
in the management of
acute coronary syndromes
because fentanyl
has a higher potency
shorter onset and
fewer side effects.
12:52
So that covers
management for steady.
12:55
Now, let's go back
to our ACS algorithm
and consider the
opposite possibility.
12:59
So we perform our
history and physical,
we're concerned about
coronary disease.
13:03
We've performed our ECG
looking for a STEMI,
but now we haven't found one.
13:08
There is no criteria to send the patient
to the cardiac catheterization lab.
13:12
So our next maneuver is
going to be to assess
their level of risk
for coronary disease.
13:19
So for patients who
don't have STEMIs,
but you're still concerned
about coronary syndromes.
13:25
We want to assess their level
of risk for coronary disease.
13:28
This is our first
priority in patients
in whom we suspect a coronary syndrome
who were not sending to the cath lab.
13:35
There are a number of different decision
tools out there to help us do that.
13:38
But the one we use
most commonly in the ED
that's been validated
for use in our setting
is called the heart score.
13:44
It consists of five elements which
conveniently spell the word heart.
13:48
So the first element is history
if your patient has a very concerning
history, they get 2 points,
if they have a so-so
history, they get 1,
and then if the history is
minimally suspicious they get 0.
14:00
For ECG changes,
it's based on ST
segment depressions.
14:05
ST depressions are pretty
characteristic of coronary ischemia,
and there aren't a lot of other
conditions that cause those
so you get 2 points for those.
14:13
Whereas if you have nonspecific changes
or no changes, you get fewer points.
14:18
Age is the next variable aged
over 65 gets you 2 points,
45 to 65 gets you 1.
14:25
And if you're under 45, you're much
less likely to have a coronary syndrome.
14:29
So you get no points for that.
14:32
Risk factors address the classic
elements of risk for coronary disease and
we'll talk about those in just a few minutes.
14:39
If you have one or two risk
factors you get 1 point.
14:42
Greater than three.
You get 2 points.
14:44
No risk factors.
Obviously you get none.
14:47
The last variable
is our troponin.
14:49
So if your troponin is more
than three times the upper limit
of normal for your institution
that gets you 2 points.
14:56
If you have a small troponin leak
just a little bit of an elevation
that's less than three times that
upper limit of normal you get 1 point,
and normal troponin
is get you no points.
15:06
Now like I said,
this is not the only tool that's out there
but it is a very useful
tool that has been validated
in the emergency
department to predict
MACE or Major Adverse
Cardiac Events
and that's really our goal.
15:21
We want to identify the
patients who are at high risk
of having another MI of having
an adverse outcome like death
so that we can address
their needs urgently
and we want to identify low-risk
patients so we can send them home
and not perform a lot of
unnecessary tests on them.
15:39
So that's the purpose of this
type of a scoring system.