Acute Coronary Syndromes
At the end of this self-study the
participant will:
• Describe the pathophysiology of
Acute Coronary Syndromes
• List signs and symptoms of:
– Stable angina
– Unstable angina
– Acute myocardial infarction
1
What is ACS?
• The term Acute Coronary Syndrome (ACS) includes a
constellation of syndromes: chest pain, unstable angina,
non ST elevation MI (Non-STEMI) and ST elevation MI
(STEMI).
• The American College of Cardiology (ACC) and
American Heart Association (AHA) recommends that
health care providers use the term ACS as a provisional
diagnosis and once the diagnosis is made use the term that
applies: Chest Pain Syndrome, Unstable Angina, Non-Q
wave MI and Q-wave MI.
• Mortality rates and the risk associated with ACS is the
greatest during the first 30 days after presentation and
stabilizes to a lower rate after 30 days, validating the
importance of early diagnosis and treatment.1
2
ACS: Triad of I’s
Ischemia vs. Injury vs. Infarction
All represent an oxygen supply problem:
• Ischemia = reversible
• Injury = acute period of both ischemia and infarction
• Infarction = irreversible cell death
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ACS
• Unstable angina (U/A)
– a clinical syndrome usually resulting from
disrupted atherosclerotic plaque, which
subsequently results in an imbalance between
myocardial oxygen supply and demand.
– U/A and Non-STEMI are closely related in
presentation.
– ECG may show ST depression,
• or be normal
– Cardiac enzymes are normal
– Ischemia is reversible
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ACS
• Non-ST Elevation Myocardial Infarction (Non-STEMI)
– Differs from unstable angina mostly due to severity of
ischemia
– Non-STEMI causes enough myocardial damage to
release detectable cardiac markers indicating
myocardial injury [Troponin I (TnI), Troponin T
(TnT), and/ or Creatinine kinase( CK-MB)].1
– ECG changes may occur
• No sustained ST segment elevation.
– Can limit the area of infarction through medical and
nursing interventions
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ACS
• ST Elevation Myocardial Infarction (STEMI)
– a loss of cardiac myocytes as a result of prolonged
ischemia due to a perfusion-dependent imbalance
between supply and demand.
– Myocardial ischemia does not cause immediate cell
death but rather it occurs over a finite period of
time. It can take at least 4 to 6 hours for complete
necrosis of myocardial cells
– This is dependent upon the presence of collateral
blood flow into the ischemic zone or coronary
artery occlusion.2
6
Examples of ST changes in STEMI
ECG changes that commonly occur
with increasing levels of coronary
artery occlusion
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Signs and Symptoms Overview
• Only 30-40% of all MI’s present with typical S & S’s.
• 60-70% exhibits less typical symptoms:
– Women exhibit less obvious symptoms than men
– If over age 75, syncope is the main symptom
– Diabetics express very non-specific symptoms
– What if you are a diabetic female over the age of
75?
• Cardiac risk factors must play an important role in
deciding who receives a 12-lead ECG and who does
not.
8
Cardiac Risk Factors
9
Factors That Can’t Be
Changed
Factors that can be
changed or controlled
Heredity
Gender
Age
Smoking
Hypertension
Hypercholsterolemia
Obesity
Physical Inactivity
Stress
Diabetes
History of Presenting Illness
• The most important diagnostic
information is the patient’s “story”
–
–
–
–
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Current symptoms
Time of onset
Pain assessment
Past medical history / medications
“Typical” Signs
and Symptoms of
MI
• Chest discomfort:
– Crushing, pressure,
tightness
– Sustained
– Unrelieved or partially
relieved by rest
– Unrelieved or partially
relieved by nitroglycerin
– Pain may radiate to other
areas
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Associated
Signs and
Symptoms of MI
• Denial
•
•
•
•
•
•
Chest discomfort
Syncope/weakness
Cool/pale/diaphoretic
Dyspnea
Nausea/vomiting
Sense of impending
doom
PQRST: Eliciting
pain information
• P: Placement/
provocation/
precipitating factors
• Q: Quality
• R: Radiation, relief and
reproducibility
• S: Severity (0-10 scale)
• T: Time of onset
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Women’s Issues
•
•
•
•
•
•
Heart disease leading cause of death
Sharp rise in smoking-related illness
1/3 of adult women are sedentary
1 in 3 women are overweight
More nonfatal chronic conditions
Less available supports
– Because many chronic conditions are
disabling, middle-aged and older women
are about 80% more likely than men to
report difficulties in taking care of
themselves.
U.S. Dept. Health & Human Services, Special Profile Women’s Health, 1996.
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Cardiac Symptoms
in the Elderly
• Acute or progressive
dyspnea
• Extreme fatigue
• Abdominal pain
• Nausea & vomiting
• Syncope
• Congestive heart failure
• Weakness/falls
• Pain in other places (not
chest)
Nowak, KA. Nurse Pract. 1997. 22:1114.
14
AMI Statistics in
the Elderly
• Higher in-hospital
mortality
• Higher post-discharge
mortality
• Do not have larger
infarcts
FTT Collaborative Group. Lancet. 1994;343:311.
White, HD, et al. Circulation. 1996;94:1826-1833.
Miller, TD,et al. Circulation. 1997; 96 (suppl):
Abstract 149.
Diabetes & Acute MI
• Independent predictor of mortality (mechanism
unknown)
• Lowest mortality in patients who received fibrinolytics
• Diabetic patients:
– Were older and more often female
– Had more anterior MIs and triple vessel CAD
– Presented later and were treated later
• Left ventricular function may differ from those w/o
diabetes due to possible impaired left ventricular
performance in non-MI zones
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Mak, KH, et al. JACC. 1997; 30:171.
Woodfield, SL, et al. JACC;1996; 29:35. Strandberg, LE, et al. J Int Med.
2000; 248:119
Mak, KL & Topol, TJ. JACC. 2000; 35: 563-8
Goal: Early Reperfusion Therapy
• Reperfusion Therapy
– Defined as the initial strategy employed to restore
blood flow to the occluded coronary artery by two
standards of care
• Fibrinolytic therapy
• Primary percutaneous transluminal coronary
angioplasty (PTCA)
• Outcomes Dependent Upon:
– Time to treatment
– Early and full restoration of blood flow
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Next: ACS Diagnostics
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