ACUTE CORONARY SYNDROME
UPDATE
Charles Shoalmire, MSN, RN, ACNP -BC
Objectives
At the conclusion of this activity, participants will be
able to:
• Recognize ST elevation MI
• Differentiate current subtypes of acute coronary
syndrome (ACS)
• Discuss appropriate initial treatment algorithm for
different subtypes of ACS
Definition of Acute Coronary Syndrome
• Acute coronary syndrome (ACS) refers to a
spectrum of clinical presentations ranging from
those for ST-segment elevation myocardial
infarction (STEMI) to presentations found in non–STsegment elevation myocardial infarction (NSTEMI)
or in unstable angina. In terms of pathology, ACS is
almost always associated with rupture of an
atherosclerotic plaque and partial or complete
thrombosis of the infarct-related artery.
http://emedicine.medscape.com/article/1910735-overview
Defintion of Acute Coronary Syndrome
• In some instances, however, stable coronary artery
disease (CAD) may result in ACS in the absence of
plaque rupture and thrombosis, when physiologic stress
(eg, trauma, blood loss, anemia, infection,
tachyarrhythmia) increases demands on the heart. The
diagnosis of acute myocardial infarction in this setting
requires a finding of the typical rise and fall of
biochemical markers of myocardial necrosis in addition
to at least 1 of the following:
• Ischemic symptoms
• Development of pathologic Q waves
• Ischemic ST-segment changes on electrocardiogram (ECG) or
in the setting of a coronary intervention
http://emedicine.medscape.com/article/1910735-overview
Universal Definition of MI
• ESC/ACCF/AHA/WHF Expert Consensus Document
(2012) divides myocardial infarction into five
different subtypes:
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ST Elevation Myocardial Infarction—STEMI—Type I
Non-ST Elevation Myocardial Infarction—NSTEMI—Type I
Type II
Type III
Type IV
Type V
Review of ECG Interpretation
Characteristics of STEMI (Type I)
• Plaque rupture
• Intraluminal coronary artery thrombus formation
• Associated ECG changes
• Spontaneous MI related to atherosclerotic plaque rupture,
ulceration, fissuring, erosion, or dissection – with associated
thrombus leading to decreased distal flow and ensuing
myocyte necrosis.
• This may be – on occasion associated with non-occlusive
CAD
STEMI on ECG
•
http://www.virtualmedstudent.com/links/cardiovascular/acute_coronary_syndromes.html&docid=I6WHDB796ClTfM&imgurl=http://www.virt
ualmedstudent.com/images/stemi.jpg&w=2558&h=1105&ei=zB3GUIGdDebR2QWIGoCA&zoom=1&iact=rc&dur=494&sig=100654779536327
798686&page=2&tbnh=107&tbnw=248&start=8&ndsp=16&ved=1t:429,r:12,s:0,i:189&tx=128&ty=57
STEMI ECG Criteria
• ≥ 2 mm of ST segment elevation in 2
contiguous precordial leads in men (1.5 mm
for women)
• ≥ 1mm in other leads (2 contiguous)
• An initial Q wave or abnormal R wave
develops over a period of several hours to
days.
• Within the first 1-2 weeks (or less), the ST
segment gradually returns to the isoelectric
baseline, the R wave amplitude becomes
markedly reduced, and the Q wave deepens.
In addition, the T wave becomes inverted.
STEMI ECG Criteria
• In addition to patients with ST elevation on
the ECG, two other groups of patients with
an acute coronary syndrome are
considered to have an STEMI:
• those with new or presumably new left bundle
branch block
• those with a true posterior MI
• An elevation in the concentration of
troponin or CK-MB is required for the
diagnosis of acute MI
STEMI ECG Criteria
• Anterior STEMI: ST elevation in the precordial
leads + I and aVL (LAD territory)
• Posterior STEMI: reciprocal ST depressions in
V1-V3 (ST elevation in post leads), may have
component of inferior ischemia as well (ST
elevations in II, III and aVF)
• Often occurs w/ inferior MI (L Cx)
• Inferior STEMI: ST elevation in II. III and aVF (+
ST elevation in R-sided precordial leads),
reciprocal changes in I and aVL (R coronary
or L Cx)
STEMI
• http://www.thrombosisadviser.com/html/images/library/atherothrombosis/stemi-andnstemi-ecg-illustration-PU.jpg
ECG Challenge
• 50 year old male with no known past medical history
presents to the ED with new onset left-sided chest
pain for one hour.
• www.emergencymedicine.ucla.edu/ecgchallenge/
• http://www.emergencymedicine.ucla.edu/ECGChal
lenge/MainGUI.html
Characteristics of NSTEMI (Type I)
• Evidence of necrosis consistent with acute ischemia
• A rise and/or fall of cardiac enzyme (specifically
troponin I) plus any ONE of these findings meets MI
requirements:
• Symptoms of ischemia
• New (or presumed new) significant ST-segment/T-wave
changes OR a new LBBB
• Pathological Q waves
• Radiologic evidence of loss of viable myocardial tissue at
the cellular level OR new regional wall motion abnormality
• Intracoronary thrombus by angiography or autopsy
Thygesen, K., Alpert, J. S., Jaffe, A. S., Simoons, M. L., Chaitman, B. R., & White, H. D. (2012). Third universal
definition of myocardial infarction. Circulation, 126. pp. 2020-2035. doi 10.1161//cur,0b013e3182e1058
Pathologic Q Waves
• Any Q-wave in leads V2–V3 ≥ 0.02 s or QS complex
in leads V2 and V3
• Q-wave ≥ 0.03 s and > 0.1 mV deep or QS complex
in leads I, II, aVL, aVF, or V4–V6 in any two leads of a
contiguous lead grouping (I, aVL,V6; V4–V6; II, III,
and aVF)
• R-wave ≥ 0.04 s in V1–V2 and R/S ≥ 1 with a
concordant positive T-wave in the absence of a
conduction defect
Pathologic Q Waves
NSTEMI
•
http://www.virtualmedstudent.com/links/cardiovascular/acute_coronary_syndromes.html
NSTEMI (Type I)
• http://www.thrombosisadviser.com/html/images/library/atherothrombosis/stemi-andnstemi-ecg-illustration-PU.jpg
Characteristics of Type II
• Instance of myocardial injury with necrosis when a
condition other than CAD contributes to an imbalance
between myocardial oxygen supply and/or demand
• Coronary endothelial dysfunction
• Coronary artery spasm
• Coronary embolism
• Tachy-/brady-arrhythmias
• Anemia
• Respiratory failure
• Hypotension
• Hypertension with our without LVH
Characteristics of Type III
• Cardiac death with symptoms suggestive of
ischemia and presumed new EKG ischemic
changes or new LBBB
• Death occurred before cardiac enzymes were
obtained or before the values had increased
Characteristics of Type IVa
• MI associated with PCI defined by an elevation of
cTn values of >5X 99th percntile URL in patients with
a normal baseline cTn
• >20% if the baseline value is elevated and
are stable or falling in addition:
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Symptoms of MI
New ECG changes or new LBBB
Aniographic evidence of loss of patency
Imaging demonstration loss of viable
myocardium or new regional wall motion
abnormality
Characteristics of Type IVb
• MI associated with stent thrombosis detected by
angiography or autopsy in the setting of MU with a
rise and or fall of cardiac enzymes
Characteristics of Type V
• MI associated with CABG
• Defined by elevation of cardiac biomarker >10x
99th percentile URL in patents with normal baseline
values in addition:
• New pathological Q waves or new LBBB
• Angiographic evidence of new graft or new
native coronary artery occlusion
• Imaging evidence of loss of viable myocardium
or new regional wall motion abnormality.
Characteristics of Unstable Angina
• The traditional term of unstable angina was
first used 3 decades ago and was meant to
signify the intermediate state between
myocardial infarction and the more chronic
state of stable angina.
• Unstable angina is considered to be an
acute coronary syndrome in which there is
no release of the enzymes and biomarkers
of myocardial necrosis.
Selecting the Appropriate Algorithm
• STEMI – preferred treatment in a center with PCI
capability:
• PTCA with a target door to wire time <90 minutes.
• Fibrinolics are an acceptable choice
• Medical management for certain patient
populations
• NSTEMI – primary PCI is acceptable
• Medical management is an acceptable choice
Non-Pharmacologic Interventions
• Percutaneous transluminal coronary angioplasty
(PTCA)
• Intra-aortic balloon pump
• Coronary artery bypass graft (CABG)
Pharmacologic Interventions
STEMI
Fibrinolytics
Unfractionated heparin
Dual platelet inhibition
Beta blockade
ACE inhibition for LV dysfunction
Consideration of minerocorticoid receptor
antagonism for LV dysfunction, e.g. EF < 40%
• Spironolactone or Inspra (epleronone)
• Statin
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Non-Pharmacologic Interventions NSTEMI
• Percutaneous transluminal angioplasty
• Coronary artery bypass grafting
Pharmacologic Interventions
NSTEMI
• Dual platelet inhibition
• Aspirin and Plavix or other thienopyridine
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Beta blockade
Nitrates
ACE inhibition for LV dysfunction
Consideration of minerocorticoid receptor
antagonism for LV dysfunction, e.g. EF < 40%
• Spironolactone or Inspra (epleronone)
• Statin
• Fractionated or unfractionated heparin
Treatment of USA
• For all practical purposes, the treatment algorithm
for NSTEMI is appropriate for unstable angina
Conclusion and Questions
• Five different categories of MI
• Differences on ECG, lab values, etc.
• Priority acute treatment for STEMI
• Priority acute treatment for NSTEMI
• Questions?