Acute Coronary Syndrome
MINI LECTURE
KELVIN NGUYEN
OBJECTIVES
 Definition of ACS
 UA, NSTEMI, and STEMI
 Risk stratification in NSTEMI
 Management
Acute Coronary Syndrome
Definition: a constellation of symptoms related to
obstruction of coronary arteries with chest pain being the
most common symptom in addition to nausea, vomiting,
diaphoresis etc.
Chest pain concerned for ACS is often radiating to the left
arm or angle of the jaw, pressure-like in character, and
associated with nausea and sweating. Chest pain is often
categorized into typical and atypical angina.
Acute coronary syndrome
 Based on ECG and cardiac enzymes, ACS is classified
into:
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STEMI: ST elevation, elevated cardiac enzymes
NSTEMI: ST depression, T-wave inversion, elevated cardiac
enzymes
Unstable Angina: Non specific EKG changes, normal
cardiac enzymes
Unstable Angina
 Occurs at rest and prolonged, usually lasting >20
minutes
 New onset angina that limits activity
 Increasing angina: Pain that occurs more frequently,
lasts longer periods or is increasingly limiting the
patients activity
EKG
 STEMI:
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Q waves , ST elevations, hyper acute T waves; followed by T wave
inversions.
Clinically significant ST segment elevations:
> than 1 mm (0.1 mV) in at least two anatomical contiguous leads
 or 2 mm (0.2 mV) in two contiguous precordial leads (V2 and V3)

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Note: LBBB and pacemakers can interfere with diagnosis of MI on
EKG
EKG
 NSTEMI:
 ST depressions (0.5 mm at least) or T wave inversions ( 1.0
mm at least) without Q waves in 2 contiguous leads with
prominent R wave or R/S ratio >1.
 Isolated T wave inversions:
can correlate with increased risk for MI
 may represent Wellen’s syndrome:
 critical LAD stenosis
 >2mm inversions in anterior precordial leads

 Unstable Angina:
 May present with nonspecific or transient ST segment
depressions or elevations
Cardiac Enzymes
 Troponin is primarily used for diagnosing MI
because it has good sensitivity and specificity.

CK-MB is more useful in certain situations such as post
reperfusion MI or if troponin test is not available
 Other conditions can cause elevation in troponin
such as renal failure or heart failure
 The increasing troponin trend is the important thing
to look for in diagnosing MI. Order Troponin
together with ECG when doing serial testing to rule
out ACS.
Risk Stratification: TIMI score
 NSTEMI or unstable angina are risk stratified:
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Age>=65
>= 3 CAD risk factors:
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HTN, hyperlipidemia, diabetes, smoker, family hx of early MI
Documented CAD with >=50% stenosis
ST segment deviation
≥ 2 aginal episodes in past 24 hours
Aspirin use in the past week (marker for more severe case)
Elevation of cardiac enzymes
 Stratify risk based on number of variables
 Risk:

0-2: Low
3-4: Intermediate
5-7: High risk
NSTEMI & Unstable Angina Management
 NSTEMI or EKG changes suggest ischemia with high risk:
 Telemetry
 Aspirin
 Beta blocker
 Nitrates
 Heparin (UFH or LMWH)
 ACE-I/ARB
 Statin
 Consider GP IIb/IIIa inhibitor and clopidogrel
 EKG normal or non-specific changes with intermediate or low
risk:
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Telemetry
Rule out ACS with 3 sets of troponin, EKG
Consider pre-discharge stress test
STEMI Management
 STEMI patients usually go straight to the cath lab from
the ED. Goal: door to balloon 90 minutes.
 Initial management for STEMI:
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Cardiac monitor
Supplemental O2
Nitrates*
Beta blocker
Morphine
Clopidogrel
Aspirin
Good IV access
Call cardiology fellow!
Case
 60 year old male with history of DM2 for 20 years,
HTN, HLD who presented to the ED with 4 hour
onset of chest pain which was described as in the
anterior chest without radiation. The pain seemed to
improve when he sits down and worsening when he
walked upstairs.
 VS: T 36.9, HR: 95, BP: 84/56, RR 22, O2 sat. 99%
RA.
 ECGs are shown as followed
 What will you do?
 What’s your diagnosis?
 What should be done now?
References
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2005 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency
Cardiovascular Care. Circulation 2005;112:IV-89-IV-110
2013 ACCF/AHA Guideline for the Management of ST-Elevation Myocardial Infarction : A Report of
the American College of Cardiology Foundation/American Heart Association Task Force on Practice
Guidelines. Circulation 2013, epublished April 29th 2013 and print published june 4th 2013.
Herman LK, et al. Comparison of frequency of inducible myocardial ischemia in patients presenting to
emergency department with typical versus atypical or nonanginal chest pain. Am J Cardiol. 2010
105:1561-4.
 www.uptodate.com:
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Overview of the acute management of unstable angina and acute non-ST elevation myocardial infarction
Initial evaluation and management of suspected acute coronary syndrome in the emergency department
Criteria for the diagnosis of acute myocardial infarction