Chapter 27
Acute Coronary Syndrome
and Myocardial Infarction
Dr. Maysoon S. Abdalrahim
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Acute coronary syndrome (ACS)
is an emergent situation characterized by an acute
onset of myocardial ischemia that results in
myocardial death (i.e., MI).
the terms coronary occlusion, heart attack, and
myocardial infarction are used synonymously, the
preferred term is myocardial infarction.)
unstable angina,
NSTEMI
(STEMI)
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Pathophysiology: Myocardial Infarction
Unstable angina
Rupture of an atherosclerotic
plaque  reduced blood flow
in a CA (not completely
occluded)  preinfarction
angina.
Myocardial infarction
Plaque rupture and thrombus formation
Myocardial ischemia (complete occlusion of
CA)  an area of the myocardium is
permanently destroyed  myocardial death
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Pathophysiology: Myocardial Infarction
Other causes of MI= intense imbalance between
myocardial O2 supply and O2 demand
Vasospasm of a CA
decreased O2 supply (bleeding, anemia, or low BP)
Increased O2 demand (tacky cardia, thyrotoxicosis,
cocaine)
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Pathophysiology: Myocardial Infarction
The area of infarction develops over minutes to hours.
“time is muscle”: the urgency of appropriate treatment
to improve patient outcomes.
The ECG identifies the type and location of the MI, and
the timing.
The goals of therapy are to prevent or minimize
myocardial tissue death and prevent complications
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Clinical Manifestations: Myocardial Infarction
Chest pain
 sudden and continous despite rest and medication
 Patients may have sympathetic NS symptoms
 chest pain
 shortness of breath
 indigestion, nausea
 Anxiety
 cool, pale, and moist skin
 Rapid heart rate and respiratory rate
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Diagnostic Findings: Myocardial Infarction
Patient History
The symptom
History of previous cardiac and other illnesses
Family history of heart disease.
The risk factors for heart disease
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Diagnostic Findings: Myocardial Infarction
Electrocardiogram
For diagnosing an acute MI.
It should be obtained within 10 minutes from the time a
patient reports pain or arrives in the ED.
serial ECG changes over time, the location, and
resolution of an MI.
The classic ECG changes are
 T-wave inversion
 ST-segment elevation
 an abnormal Q wave
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Electrocardiogram
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Electrocardiogram
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Diagnostic Findings: Myocardial Infarction
patients are diagnosed with one of the forms of ACS:
 Unstable angina : CA ischemia, but ECG shows no
evidence of acute MI.
 STEMI: ECG evidence of acute MI + changes in
two leads
 NSTEMI: elevated cardiac biomarkers but no
definite ECG evidence of acute MI.
During recovery from an MI, the ST segment is the first
ECG indicator to return to normal (1 to 6 weeks). Qwave changes are permanent.
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Diagnostic Findings: Myocardial Infarction
Echocardiogram
to evaluate ventricular function when the ECG is nondiagnostic.
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Diagnostic Findings: Myocardial Infarction
Laboratory Tests
Cardiac enzymes and biomarkers to diagnose an AMI.
 myoglobin and troponin: analyzed rapidly
 Creatine Kinase and Its Isoenzymes: CK-MB
increase within a few hrs and peaks within 24hrs
 Myoglobin: a heme protein (transport O2). starts to
increase within 1 to 3 hrs and peaks within 12 hrs
 Troponin: a protein regulates the myocardial
contraction that have 3 isomers : C, I, and T.
reliable and critical markers of MI. detected within
a few hrs and remains elevated for 3 weeks
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Diagnostic Findings: Myocardial Infarction
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Diagnostic Findings: Myocardial Infarction
Cardiac Catheterization (cardiac cath) is a procedure that
examines the inside of the heart's blood vessels using special Xrays called angiograms. Dye visible by X-ray is injected into blood
vessels using a thin hollow tube called a catheter.
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Diagnostic Findings: Myocardial Infarction
Cardiac Catheterization (cardiac cath)
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Diagnostic Findings: Myocardial Infarction
Coronary Stent is a tiny wire mesh tube used to prop open an
artery during angioplasty. The stent stays in the artery
permanently. The stent will also improve blood flow to the heart
muscle and will relieve chest pain (angina).
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Medical Management: Myocardial Infarction
The goals are to minimize myocardial damage,
preserve myocardial function, and prevent
complications.
These goals are facilitated by the use of guidelines
developed by the American College of Cardiology
(ACC) and the AHA (Chart 27-7).
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27-7
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Medical Management: Myocardial Infarction
Pharmacologic Therapy
Aspirin, nitroglycerin, morphine, an IV beta-blocker,
and other medications
Patients should continue the beta-blocker throughout
hospitalization
LMWH + platelet-inhibiting agents to prevent further
clot formation.
NSAIDS may be discontinued because of SE
Analgesics: morphine in IV boluses
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Medical Management: Myocardial Infarction
Pharmacologic Therapy
 Aspirin administered upon arrival to the hospital and at
discharge from the hospital
 Angiotensin converter enzyme inhibitor for patients with
concomitant left ventricular systolic dysfunction
 No smoking cessation advice/counseling
 Beta-blocker prescribed at discharge
 Thrombolytic (fibrinolytic) therapy received within 30 minutes of
hospital arrival
 PCI received within 90 minutes of hospital arrival
 Statin prescribed at discharge
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Medical Management: Myocardial Infarction
Pharmacologic Therapy
Angiotensin-Converting Enzyme Inhibitors (ACE)
inhibitors prevent the conversion of angiotensin I to
angiotensin II BP decreases and diuresis (decrease
O2 demand).
Thrombolytics: IV in a specific protocol (Chart 28-8).
The purpose is to dissolve the thrombus in a CA
 must be administered within 3 to 6 hours for
patients with ECG evidence of acute MI, and
should be initiated within 30 minutes of
presentation to the hospital (door-to-needle time).
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Medical Management: Myocardial Infarction
Emergent Percutaneous Coronary Intervention (PCI)
used to open the occluded CA increase O2 supply.
should be performed within 60 minutes (door-toballoon time).
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Cardiac Rehabilitation: Myocardial Infarction
After the patient with an MI is free of symptoms
 education, individual and group support, and
physical activity.
The goal: to improve the quality of life.
 limit the effects and progression of atherosclerosis
 return to work and pre illness lifestyle
 enhance psychosocial and vocational status
 prevent another cardiac event.
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Nursing Interventions: Myocardial Infarction
Relieving Pain and Symptoms of Ischemia
Balancing O2 supply with O2 demand
 relief of chest pain is the top priority
 O2 by nasal cannula in a rate of 2 to 4 L/min,
saturation levels of 96% to 100%
 Medication therapy
Vital signs
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Nursing Interventions: Myocardial Infarction
Relieving Pain and Symptoms of Ischemia
Physical rest in bed with the back elevated to
decrease chest discomfort and dyspnea.
 Tidal volume improves
 Drainage of the upper lung lobes improves.
 venous return to the heart (preload) decreases
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Nursing Interventions: Myocardial Infarction
Improving Respiratory Function
Regular assessment to detect early signs of
pulmonary complications.
Monitor fluid volume status to prevent overloading
Encourage deeply breathing exercises
Change position frequently
Pulse oximetry
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Nursing Interventions: Myocardial Infarction
Promoting Adequate Tissue Perfusion
Bed or chair rest to reduce O2 oxygen demand and
remain until the patient is pain free and stable.
check skin temperature and peripheral pulses
frequently to monitor tissue perfusion.
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Nursing Interventions: Myocardial Infarction
Reducing Anxiety
To reduce the sympathetic stress  decrease O2
demand and relieve pain
Develop a trust and caring relationship
Provide information
Ensure a quiet environment, promote sleep, using
caring touch, relaxation techniques, using humor, and
providing spiritual support
An atmosphere of acceptance
Music therapy and pet therapy
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Nursing Interventions: Myocardial Infarction
Monitoring and Managing Complications
the Plan of Nursing Care in Chart 28-10.
monitor the patient closely for changes in cardiac rate
and rhythm, heart sounds, BP, chest pain, respiratory
status, urinary output, skin color and temperature,
sensorium, ECG changes, and laboratory values.
Report rapidly any changes in the patient's condition
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Nursing Interventions: Myocardial Infarction
Teaching patients self-care.
provide adequate education about heart-healthy living
facilitate the patient’s involvement in a cardiac
rehabilitation program
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