Now, we're gonna talk about acute coronary syndromes,
a very common and important problem in the Emergency Department.
So coronary syndrome is actually very common.
In the United States,
there are more than three quarters of a million cases
of coronary syndromes each year.
The mean age is 68 years of age.
But the inner quota ratio goes from 56 to 79.
So this is really a disease process
that affects pretty much all adults.
There is a male to female predominance.
So for every 10 patients with coronary syndromes,
6 will be men, 4 will be women,
and 70% of coronary syndromes
are non ST segment elevations.
Meaning, these are not acute MIs
that are getting rushed to the Cath Lab.
These are patients who have more subtle findings
or in some cases even no findings on their initial ECGs.
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.
we’re not seeing big acute coronary occlusions,
we are seeing more subtle ischemia.
Short term mortality is stable across the boards,
so there's not really been any change
in the likelihood of people dying
from coronary syndromes in the short term.
long term survival is improving
and that’s largely due to improvements in diagnosis,
short term and long term management for these patients.
So what is a coronary syndrome?
Very simply, an acute coronary syndrome is any new condition
that leads to inadequate myocardial perfusion relative to demand.
So if the heart’s not getting enough oxygen,
it’s not getting as much as it needs metabolically
that is a coronary syndrome.
Now, most coronary syndromes start with chest pain.
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.
Among patients with coronary syndromes,
there’s a continuum of disease.
So patients may have unstable angina,
patients may have non ST segment elevation
or patients may have ST segment elevation myocardial infarctions.
So this is a continuum of disease acuity
and there's different management
depending on the patient's clinical presentation.
When we look at unstable angina,
we're generally talking about ischemic chest pain
that occurs either while the patient’s at rest
or with levels of exertion
that they're normally able to tolerate.
I go out for a-two-mile walk every day and usually I'm fine
but 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.
For these patients,
when they come see you in the Emergency Department
will often have no ECG findings
or their ECG findings will be very non-specific
and their lab abnormalities will be negligible as well.
So these patients are not gonna typically
present to you with elevated troponins.
patients who have NSTEMIs or none ST elevation MIs,
these are patients who can have ischemic chest pain
in any setting,
it might only be with exertion,
it might be at rest.
When they present,
they will typically have some degree of EKG changes,
although a small percent will have none.
those changes are gonna usually be ST segment depressions.
They're not gonna be elevations
because that’s a different type of infarct.
And these patients are really characterized
by their elevated troponins.
So they come in with chest pain,
they have EKGs that are not definitively diagnostic if an MI,
but they show that they have elevated troponins
and that’s evidence of coronary ischemia.
That’s our NSTEMI patient.
And then lastly,
we have our STEMI patients
or patients with ST elevation MIs
And these patients again,
have chest pain that might occur at rest,
it might occur during exertion
but it's typically a single acute event
and they're gonna come in with the classic ST segment elevations
that we all learned in medical school
characterized acute myocardial infarctions.
Now, for these patients,
they will typically have elevated troponins,
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 gonna be hanging around the ED for long enough
for us to see there troponins go up.
So that’s gonna be more of an inpatient finding
and we’re gonna make that diagnosis based on EKG findings alone
while they're in the Emergency Department.
So when we see patients with chest pain
and we suspect coronary syndromes,
we always wanna get a rapid history and physical.
We wanna know what was happening when the pain started.
How did it start?
What did it feel like?
What are all the circumstances surrounding this presentation
and we wanna get an ECG
and we wanna do that very, very quickly
typically within 10 minutes of the time
the patient arrives to the door.
If they're having a STEMI,
then they need to get immediate definitive management.
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.
That's bad, right?
Time [00:05:36.12 is] myocardium.
So these patients are gonna go directly to cardiology
and get definitive management which we’ll talk about in a minute.
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.
So here's a perfect example of a STEMI.
You can see in all the anterolateral leads
so V2, V3, V4, V5, V6
also leads one in AVL,
you see tombstones, right?
These are the classic convex ST segment elevations
that we all learned about in medical school.
This is a STEMI.
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 baseline is supposed to be.
If you look at the ST segment one millimeter after the QRS complex
which is by convention where we measure it,
you can see with the new highlight
that that ST segment is way up in the air
above that isoelectric baseline,
so it’s higher than it should be.
ST segment up above it
That’s an ST segment elevation and again on this ECG,
we’re seeing it not just in the leads that are outlined
but in several leads.
In order to diagnose somebody with a STEMI.
I mentioned before we’re using the ECG
as our primary diagnostic tool.
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.
So in the anterior leads which are
V2 through V4,
the lateral leads which are V5 and 6
and 1 and aVL or the inferior leads
which are 2, 3 and AVF.
They have to have ST segment elevations
in two or more anatomically contiguous leads.
We’re typically looking for 2 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.
In all the other leads,
we're looking for one millimeter of ST segment elevation.
So when you're measuring your ST segment,
you wanna make sure that you know,
one, what your anatomy is.
So you wanna know which leads go
with which anatomical piece of the heart
and again, anterior is gonna be V2, V3, V4,
lateral is gonna be V5, V6, 1 and AVL,
and inferior is gonna be 2, 3 and AVF
So we wanna know if they’re anatomically contiguous
and we wanna know how high the ST segment is elevated
relative to the standard for that particular lead.
The second criterion for ST segment elevation diagnosis
is ST segment depression in V1 and V2
and very simply,
that represents posterior infarction.
And if you think about it,
we always put ECG leads on the anterior part of the chest
but if you're infracting the back of your heart
that image on your surface ECG
is gonna be inverted,
it's gonna look upside down and backwards.
So ST segment elevations
that are occurring in the back of the heart
will look like depressions
when they’re measured from the front of the body.
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.
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
in a left bundle pattern
that is also highly suggestive of a myocardial infarction.
So once the patient meets those criteria,
what are we gonna do about it?
Well first and foremost,
we are very rapidly going to
revascularize their coronary arteries.
ST segment elevation
means you've got complete occlusion of an artery
that is causing transmural infarction of the heart.
That is not good.
We need to get that artery opened back up and we need to save
whatever myocardial tissue we can that’s distal to it.
The best way to accomplish that by far
is with Percutaneous Coronary Intervention or PCI.
That refers to going to the Cath Lab,
inserting stents to hold the coronaries open.
The other option that’s available is thrombolysis.
That involves giving a clot busting drug systemically.
However, it's not as effective as PCI and it’s not as safe.
So anytime you have the option of performing PCI,
that's always gonna be the preferred technique,
provided you can do it in a timely manner.
So the goal door to balloon time for PCI
should be under 90 minutes.
If you're over 90 minutes,
you don't think you’re gonna be able to get the patient
to a center where they can perform PCI in a 90-minute timeframe,
unfortunately, that piece of heart
that’s distal to that occluded coronary artery
is gonna die,
so you need to go to plan B which is gonna be again,
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.
But if you happen to be practicing
in a limited resources setting,
thrombolysis might be your only option
to save the threatened piece of the patient’s myocardium.
So it is something we should be aware of
in our armamentarium
even though we prefer PCI.
In addition to revascularization
while you're waiting for your patient to go to the Cath Lab,
you wanna make sure that you optimize their medical management.
So we're gonna give them antiplatelet therapy
in the form of aspirin and an antiplatelet agent
such as clopidogrel or ticagrelor.
We can also think about an oral beta blocker
if there's no contraindication to doing that.
Now, beta blockers in the acute setting
are not nearly as important as they are long-term
following the myocardial infarction.
But for patients who have significant hypertension
or tachycardia on arrival,
it might decrease strain on the heart
and ultimately improve their outcomes.
So you can think about it
although it's not mandatory to give up front.
We do definitely wanna provide anticoagulation
usually in the form of unfractionated heparin
for patients who are gonna be going to the Cath Lab
for the simple reason that
in the event they have a bleeding complication,
we wanna be able to turn it off and not have
uncontrolled anticoagulants kicking around in their system,
preventing us from being able to control their bleeding.
And then lastly, we wanna think about analgesia.
So typically either nitroglycerin or morphine is used
if there's not a contraindication.
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 [00:12:34.10 refracturating in nitroglycerin]
because we do wanna alleviate our
patient’s suffering in addition to giving them
the definitive treatment that they need.
So that covers management for STEMI.
Now, let’s go back to our ACS algorithm
and consider the opposite possibility.
So we perform our history and physical,
were concerned about coronary disease.
We’ve performed our ECG looking for a STEMI
but now we haven't found one.
There is no criteria
to send the patient to the Cardiac Catheterization Lab.
So our next maneuver is gonna be to assess
their level of risk for coronary disease.
So for patients who don't have STEMIs
but you're still concerned about coronary syndromes,
we wanna assess their level of risk for coronary disease.
This is our first priority in patients
in whom we suspect a coronary syndrome
who we’re not sending to the Cath Lab.
There are a number of different decision tools
out there to help us do that
but the one we use most commonly in the ED
that’s been validated for use in our setting
is called the heart score.
It's consist of five elements
which conveniently spell the word heart.
So the first element is history.
If your patient has a very concerning history,
they get two points.
If they have a so-so history,
they got one,
and then if the history is minimally suspicious,
they get zero.
For ECG changes,
it's based on ST segment depressions.
ST depressions are pretty characteristic of coronary ischemia,
and there aren’t a lot of other conditions that cause those,
so you get two points for those.
Whereas, if you have nonspecific changes
or no changes, you get fewer points.
Age is the next variable.
Age over 65 gets you 2 points,
45 to 65 gets you 1,
and if you're under 45,
you’re much less likely to have a coronary syndrome,
so you get no points for that.
Risk factors address the classic
elements of risk for coronary disease
and we’ll talk about those in just a few minutes.
If you have one or two risk factors,
you get one point,
greater than three, you get two points,
no risk factors, obviously, you get none.
The last variable is our troponin.
So if your troponin is more than
three times the upper limit of normal for your institution,
that gets you two points.
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 one point and normal troponins gets you no points.
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.
We wanna 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 wanna identify low risk patients
so we can send them home
and not perform a lot of unnecessary tests on them.
So that’s the purpose of this type of a scoring system.