Download Acute Myocardial Infarction. The understanding of acute myocardial

Acute Myocardial Infarction 1
Acute Myocardial Infarction
Trevor Mattarella
Delta College
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Acute Myocardial Infarction
Provider and Manager of Care Disease Process:
Acute myocardial infarction (AMI) is a leading cause of death for men and women of all
ages, races, and backgrounds. According to Ignatavicius, “Myocardial infarction occurs when
myocardial tissue is abruptly and severely deprived of oxygen (Ignativicious, 2010, p. 849).”
This condition is often caused by a blockage or occlusion of one or more coronary arteries
supplying the heart with oxygen and nutrients. The majority of myocardial infarctions are
directly related to atherosclerosis of the coronary arteries, thrombus, or rupture of plaque within
the vessel. Various factors have been found to cause acute myocardial infarction such as
coronary artery vasospasm, platelet aggregation, and emboli from mural thrombi (Ignativicious,
2010, p. 849). These factors result in decreased oxygen to myocardial tissue resulting in
ischemia, ultimately leading to injury or necrosis of myocardial tissue if proper circulation is not
restored rapidly. AMI may result over a period of several hours or longer.
Risk factors are crucial when assessing each patient’s chance of developing an AMI.
There are two types of risk factors present. These include modifiable and non-modifiable. Nonmodifiable risk factors are individual patient characteristics that cannot be changed or controlled.
Common non-modifiable risk factors are the patient’s ethnicity, age, gender, and family history.
Assessing modifiable risk factors is essential, since teaching can be initiated to prevent further
damage. By advising patients of potential problems, lifestyle changes can be initiated and future
health problems may be diminished. Modifiable risk factors for AMI are obesity, smoking, high
fat or high cholesterol diet, and sedentary lifestyle.
The following clinical manifestations are indicative of AMI. According to evidence based
practice, objective symptoms are measurable and could present as systolic blood pressure less
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than 100, pulse less than 60 or elevated venous pressure greater than 12cm H20 (Kervinen,
2008). The most common subjective symptom of AMI is substernal chest pain radiating to the
left arm lasting thirty minutes or longer without relief from sublingual nitroglycerin tablets.
Other common subjective symptoms are discomfort of the jaw, nausea, dyspnea, anxiety, fatigue,
palpitations, dizziness, confusion and shortness of breath. In addition to the clinical
manifestations, there are potential complications that may result from AMI.
The primary complication from this condition is heart failure due to the damaged cardiac
muscle tissue. Since the tissue ischemia causes decreased oxygenation, the myocardial cells
infarct. This new decrease in cardiac muscle results in decreased tissue perfusion and decreased
cardiac output. Decreased tissue perfusion and cardiac output severely deprive the body of vital
oxygen and nutrients. This may lead to generalized edema and may require high dose diuretics to
decrease the fluid accumulation. Another common complication secondary to AMI is ventricular
remodeling. Ventricular remodeling is caused by necrotic tissue shrinking and forming scar
tissue from the damaged area. According to Ignatavicius (2010), remodeling may decrease left
ventricular function, resulting in heart failure. The scarred tissue cannot contract effectively or
conduct electrical impulses as efficiently as before the insult. Once the heart is not transmitting
electrical impulses properly, chronic ventricular dysrhythmias result.
Medical and Surgical Management:
There are various laboratory values and cardiac tests used to diagnose AMI. Physicians
evaluate a collection of results to formulate a diagnosis of AMI. Once the results are obtained,
there are surgical procedures that help correct the problems within the heart muscle. The most
common laboratory values are known as troponins T and I, creatinine kinase-MB, and
myoglobin. After reviewing the laboratory values of a patient with AMI, the physician will order
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a series of other diagnostic tests to confirm the diagnosis. According to Ignativicious, the most
common diagnostic tests ordered are electrocardiogram (ECG), echocardiogram (ECHO) and
cardiac catheterization (Ignativicious, 2010, p.855). Assessing the patient’s signs, symptoms, and
response to therapy is vital nursing care for AMI.
Troponins T and I are indicative of muscle damage since myocardial muscle proteins are
released into the bloodstream during cardiac damage. Troponins T and I are not found in patients
with healthy hearts, so any small elevation in this laboratory value indicates tissue necrosis or
AMI. The expected abnormal finding in a patient with a myocardial infarction is a troponin I
elevation greater than 0.03mng/mL (Ignativicious, 2010, p. 720). This test is the quickest
laboratory value to indicate cardiac tissue damage since it rises in about six hours after insult.
Creatine kinase-MB (CK-MB) is a laboratory tests used to assist in diagnosing AMI. The CKMB determines whether tissue damage is of cardiac origin. The CK-MB will be elevated with an
AMI patient. Myoglobin levels rise as myocardial muscle damage occurs. In an AMI, the
myoglobin level will be greater than 90ng/mL (Ignativicious, 2010, p. 720).
An electrocardiogram (ECG) will be ordered for patients suspected of AMI. The
physician will usually order a twelve-lead ECG which will identify the location of ischemia or
myocardial necrosis present. According to Ignativicious (2010), expected abnormal changes
correlated with AMI are ST-elevation, T-wave inversion, or the presence of an abnormal Qwave. An echocardiogram (ECHO) is an ultrasound that measures the atria and ventricles within
the heart, and it allows for more sophisticated and complex imaging. This image is known as a
two- dimensional ECHO and has capability of displaying a cross-sectional portion of the heart,
including the blood vessels, chambers and valves. Echocardiography assists in evaluating the
patient’s prognosis directly after AMI due to defining the region and degree of ischemic injury.
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The abnormal effect after an AMI will be seen on an ECHO and the physician will likely view
portions of tissue ischemia or necrosis and heart valves or chambers functioning improperly.
Cardiac catheterization is another very significant diagnostic test related to AMI. This test can be
performed to pinpoint the extent and exact location of blockage within the coronary arteries.
Once the cardiac catheterization is completed the physician will review the results and proceed
with possible surgery if there is a significant blockage. An abnormal cardiac catheterization
result after AMI would be an ejection fraction less than fifty percent.
Medical and surgical options for patients with an ejection fraction less than forty percent
are usually corrected with percutaneous transluminal angioplasty (PCTA) or coronary artery
bypass grafting (CABG). According to evidenced based practice, PCTA is the treatment of
choice for tissue reperfusion (Kervinen, 2008). This procedure can be done prior to stent
placement and is a non-invasive technique used to restore better blood flow through the heart.
Generally a stent is required to keep the artery open after the balloon is removed, otherwise the
plaque can occlude the artery. According to Ignativicious (2010), over 500,000 coronary artery
bypass grafting surgeries are performed in the United States each year and it is the most common
procedure for older adults. A coronary artery bypass graft allows the surgeon to bypass the
occluded coronary artery with the patient’s own venous blood, arterial blood, or synthetic graft.
The surgery is performed when one or more coronary arteries have at least a seventy percent
occlusion or greater. Coronary artery bypass grafting benefits patients by restoring blood flow
through the occluded coronary artery and thus, improves tissue perfusion throughout the body.
Nursing Management:
Expected head to toe assessment findings would include the patient having acute
confusion or disorientation. The patient will likely complain of substernal chest discomfort that
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may radiate to the left arm, jaw, back, shoulder or abdomen. The pain may occur without
precipitating factors such as stress or exertion. The patient could exhibit nausea and vomiting
during an AMI. Feelings of fear and anxiety will likely be present due to the patients awareness
of what could be happening. Shortness of breath and dyspnea are common respiratory associated
symptoms due to the lungs not having adequate oxygenation during heart attack. Respiratory rate
can be increased usually above twenty per minute due to the anxious state the patient has from
AMI. The patient may display fatigue and dizziness since the body and brain are not being
perfused sufficiently. AMI patients may complain of palpitations or racing heartbeat since the
heart is attempting to overcompensate for the lack of oxygen. Epigastric distress is common
since the pain can radiate to the stomach and vomiting can worsen this condition. The patient
should be on a telemetry monitor and the electrocardiogram may show ST-elevation, STdepression, T-wave inversion, or the presence of an abnormal Q-wave indicating AMI damage.
The patients peripheral pulses may be +1, diminished due to decreased cardiac output. The skin
temperature may be cool and clammy since circulation is diminished during an AMI. Patients
may present with edema and jugular vein distention. Since the patient is experiencing an
inflammatory response, their temperature will be elevated, possibly higher than 102 degrees
Fahrenheit. A thorough assessment is crucial in implementing rapid interventions for AMI.
Nursing interventions for patient’s suffering from AMI are vital to survival. Airway is
always most important when assessing any patient but is especially imperative with any cardiac
patient. Oxygen is used to ease the heart's workload and assist the patient to breathe easier. If
oxygen is administered rapidly with an AMI, it may minimize cardiac muscle damage. Bed rest
is another method of reducing cardiac workload in an attempt to limit oxygen demand. Nurses
will see physicians order strict bed rest to achieve this goal. After administration of oxygen in the
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emergency room, a telemetry monitor should be applied to assess for ECG abnormalities.
Monitor the patient’s vital signs to assess for abnormal blood pressure, pulse, temperature,
respiratory rate, oxygen saturation, and pain. Assessing pain and treating it is very important
since AMI usually presents with pain. Morphine sulfate is the drug of choice for pain associated
with AMI. A useful resource to use for pain assessment is the PQRST mnemonic. The patient
should be asked about the precipitating event, quality, whether the pain is radiating, severity and
the timing that the pain occurs. The physician may order a Swan Ganz catheter to monitor for
complications of AMI and to assess whether medications are therapeutic. The Swan Ganz
catheter measures right atrial pressure known as central venous pressure (CVP). Left ventricular
preload can also be calculated and is known as pulmonary artery wedge pressure (PAWP).
Nursing intervention with a Swan Ganz catheter involves inflating the balloon to check the
pressures in the chambers periodically to obtain pressure readings.
Teaching plays a crucial role in preventing future heart attacks. Exercise is necessary to
help people decrease their risk of developing AMI. The proper amount and type of exercise
should be taught to patients. According to Powell, Thompson, Caspersen, and Kendrick (2007)
they stated, “Exercise acutely increases the risk of cardiovascular events, despite a reduction in
CHD with habitual physical activity.” AMI can occur through vigorous exercise, so before
starting any exercise regimen teach them to consult a doctor. Diet presents another teaching
opportunity for nurses. Since coronary artery disease is a leading cause of AMI, nurses should be
teaching patients to consume low fat, high protein, and moderate carbohydrate diets. The low fat
diet will prevent plaque deposits on the walls of the coronary arteries reducing the risk of heart
attack. Teach patients to stop smoking or using tobacco since smoking is one of the most
important risk factors for developing AMI. The chemicals in tobacco can injure the heart, veins,
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and arteries leading to atherosclerosis. Nurses should teach patients to attend annual health
screenings that will assess for hypertension, hyperlipidemia, and diabetes.
Pharmacological Management:
Medication management is necessary for patients suffering from chest pain or AMI.
According to Kervinen (2008), nitrates should be used to treat chest pain associated with
myocardial infarction. Common nitrates such as nitroglycerin (Nitrotab) vasodilate the blood
vessels and allow the heart to pump easier. Monitor the patient for hypotension, dizziness, and
palpitations. The expected response from nitrates decreases the workload of the heart. The nurse
should assess for blood pressure and pulse within normal limits and diminished or absent chest
pain. Beta-blockers such as metoprolol (Lopressor) work by relaxing blood vessels and reducing
heart rate to improve blood flow and decrease blood pressure. The nurse should assess the pulse
and blood pressure to ensure that the pulse is greater than sixty and the blood pressure is greater
than 100/60 before administering. The nurse should consider side effects including bradycardia,
bronchospasm and hypotension. Therapeutic effects of beta-blockers are to decrease the
workload of the heart and reduce blood pressure and pulse. Thrombolytic therapy uses the
classification of fibrinolytics such as alteplase (Activase) to dissolve thrombi formation in the
coronary arteries to restore blood flow. Nursing considerations should include teaching patients
to avoid situations where bruising or bleeding may occur and to use an electric razor to minimize
the risk of bleeding. Therapeutic effects of fibrinolytics with heparin can be assessed by clotting
factors studies such as APTT of fifty to seventy-five seconds and restored blood flow resulting in
improved peripheral pulses and diminished chest pain. Angiotension converting enzyme (ACE)
inhibitors are also used in AMI management. An example is quinapril (Accupril) which works
by inhibiting vasocontrictive activities of angiotensin I and II. These medications result in
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decreased blood pressure and improve the kidneys excretion of excess fluid allowing the heart to
work easier. The nurse should monitor intake and output, assess blood pressure, pulse, blood
urea nitrogen (BUN) and creatinine. Expected therapeutic results are decreased blood pressure
not below 100/60 and increased urine output greater than 35mL/hour. Anticoagulants are
necessary in addition to the other forms of medication to reduce clotting risk. Heparin and
wafarin (Coumadin) are both anticoagulants that thin the blood to prevent thrombosis and further
blood clots. Nursing considerations are monitoring the patient for bleeding and coagulation
studies such as APTT for heparin and PT and INR for Coumadin. The nurse should verify that
the therapy is working when the APTT is thirty to forty-five seconds. PT should be between ten
to twelve seconds and INR should be one to two when therapeutic levels are reached. The patient
should not show signs and symptoms of bleeding such as pulse greater than one hundred, blood
pressure less than 100/60, or bruising. Antihyperlipidemics such as pravastatin (Pravachol) are
used for patients experiencing AMI, because they inhibit low-density lipoprotein (LDL)
cholesterol from forming and increase levels of high-density lipoprotein (HDL) cholesterol.
Patients with AMI usually have hyperlipidemia since they are directly correlated. Since this class
of medications decrease cholesterol levels, it decreases the risk of developing another AMI.
While using these medications, the nurse should monitor HDL, LDL, and triglyceride levels
daily during drug therapy. The expected patient response to therapy may vary based on the type
being measured. The goal of therapy is to monitor for trends that begin to normalize and improve
from the patient’s baseline. The optimal levels for cholesterol and triglycerides are an LDL level
less than 100mg/dL, an HDL level of greater than 40mg/dL, a total serum cholesterol level less
than 200mg/dL and a triglyceride level of less than 150mg/dL.
Provider and Manager Role:
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As the provider of care for a patient who suffered an AMI, the nurse will complete a full
head-to-toe assessment including pain location, orientation level, and medical history. This
assessment will act as a baseline for the patient’s progress in order to assess improvement or
regression. The nurse may apply pain management interventions to decrease the pain. As the
provider of care, a nursing task for AMI patient would be to provide oxygen to decrease the
demands of the heart and body. This is a key intervention in reducing the damage of an AMI.
Airway is always a priority in nursing care, with AMI, it is even more significant.
As the manager of care for an AMI patient, the nurse will prioritize based on each
patient’s condition. The nursing interventions involve airway, breathing and circulation since the
problem is cardiac in origin. The patient is a priority for the nurse to assess first and to monitor
closely for changes in baseline condition. The manager of care role revolves around changing
priorities for the nurse throughout the day. As these priorities change, the manager of care is
expected to assess each need individually before choosing the most important task. Another
nursing task of the manager of care for an AMI patient is delegating and working collaboratively
with others to achieve the best result. This is significant because of the constant shifting of
priorities; the nurse must work efficiently with other team members such as nursing assistants,
licensed practical nurses, case managers, doctors, and patient family members. As the manager
of care, registered nurses are required to delegate specific tasks to other members of the team.
Proper delegation allows other staff to feel involved and permits the nurse to assess priorities of
other patients. Teamwork is an aspect of nursing that is essential to successfully treat all patients,
especially those suffering from acute myocardial infarction.
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References
Ignatavicius, D., Workman, L. (2010). Medical-surgical nursing: Patient-centered collaborative
care. St.Louis Missouri: Saunders-Elsevier.
Kervinen, H. (2008). Myocardial infarction. Finnish Medical Society. Retrieved February 2,
2010, from National Guideline Clearinghouse
http://www.guideline.gov/content.aspx?id=12794&search=acute+myocardial+infarction
Powell, K., Thompson, P., Caspersen C.,& Kendrick., J. (2007). Exercise and acute
cardiovascular events: Placing the risks into perspective. American College of Sports
Medicine. Retrieved January 18, 2010, from Wilson Web database
http://vnweb.hwwilsonweb.com.ezproxy.delta.edu:2048/hww/results/external_link_main
contentframe.jhtml?_DARGS=/hww/results/results_common.jhtml.44