Ch. 38 Acute Coronary Syndrome Flashcards Preview

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Flashcards in Ch. 38 Acute Coronary Syndrome Deck (76):

Priorities of coronary syndrome?

Perfusion and comfort


Who can have painless MI’s?

Diabetics because of neuropathy


What typically accompanies coronary events?




Insufficient 02 supply to meet requirements of myocardium



Necrosis or cell death that occurs when severe ischemia is prolonged and decreased perfusion causes irreversible damage to tissue


How much exercise per week does the American Heart Association recommends?

150 minutes


What is the number one cause of cardiogenic shock?

-Poor Peripheral pulses and cool skin are signs and should be reported ASAP


Chronic Stable Angina (CSA) Pectoris

- Strangling of the chest
- Temporary imbalance between coronary artery’s ability to supply 02 ad cardiac muscle’s demand for 02
- Ischemia limited in duration and does not cause permanent damage to myocardial tissue
- Fixed Arterial plaque = slight limit in activity
- Relieved by rest and nitro, maybe CCB - decreased O2 demand, vasodilation


Acute Coronary Syndrome (ACS) patho:

Disruption of an atherosclerotic plaque with platelet aggregation and formation of an intracoronary thrombus

Believe that atherosclerotic plaque and coronary artery rupture’s, resulting in platelet aggregation, thrombus formation or vasoconstriction (Fig. 38-1, pg. 769)


How much occlusion do you need before blood flow is impeded?




#1 arterial occlusion

Damage to endothelial lining of artery


Unstable angina (UA)

- New onset - after exertion/increased demands of heart
- Exertion increases 02 demand of the heart
- Pts may present w/ ST changes on a 12-lead ECG but do not have changes in troponin levels


Variant (Prinzmetal’s) angina

- Coronary artery SPASM - usually have to rest
- Chest pain or discomfort
- ST segment elevation during attacks, resolves when pain gone


Examples of unstable angina

New-onset angina
Variant (Prinzmetal’s) angina
Pre-infarction angina


New-onset Angina

Patients first angina symptoms, usually after exertion or other increased demands on the heart


Pre-infarction Angina

Chest pain that occurs in the days or weeks before an MI


How will the T-wave look in hyperkalemia?

Tall T-wave


How will the T-wave look in hypokalemia?

Flat T-wave


Myocardial Infarction (MI)

- Most serious acute coronary syndrome
- Myocardial tissue abruptly and severely deprived of oxygen
- Average age 65 in men and 72 in women


Occlusions of blood flow:

Ischemia -> Injury -> Necrosis


Non-ST Elevation MI (NSTEMI)

- Ruled in through serial lab work
- ST and T wave changes, indicates myocardial ischemia
- Trops elevate over next 3 - 12 hours
- ECG changes or elevated troponin should match history and physical


Causes of NSTEMI:

- Coronary vasospasm
- Spontaneous dissection
- Poor blood flow


What does an ST and T-wave changes on a 12 lead ECG indicate?

Myocardial Ischemia


What does the combination of changes on the ECG and elevation in cardiac troponin indicate?

Myocardial cell death or necrosis


ST elevation MI (STEMI):

- Indicates MI or necrosis
- ST elevation (duh)
- 100% occlusion!
- Needs immediate revascularization of blocked coronary artery


What is the number one cause of MI?

V. Fib - Pericardial thump them if witness arrest


Where do MIs often begin?

With infarction of the sub endocardial layer of cardiac muscle, which has the greatest oxygen demand and the poorest oxygen demand.


Zone of Injury

Tissue that is injured but not necrotic


Zone of ischemia

Tissues that is oxygen deprived


What is released in response to hypoxia?

- Catecholamines (epinephrine and norepinephrine)
- Pain may increase heart’s rate, contractility, and afterload
- These factors increase oxygen requirements in tissue that is already oxygen deprived, which may lead to life-threatening ventricular dysrhythmias


The actual extent of the zone of infarction depends on what three factors?

1. Collateral circulation
2. Anaerobic metabolism
3. Workload demands on the myocardium


Anterior walls MI produce what?

Bradycardia in pts



A dynamic process that does not occur instantly. Rather, it evolves over a period of hours

Infarction is necrotic


Hypoxemia from ischemia may lead to what?

Local vasodilation of blood vessels and acidosis


What may cause changes in normal conduction and contractile functions?

Potassium, calcium, and magnesium imbalances, as well as acidosis at the cellular level


When does obvious physical changes occur?

- Do not occur in the heart until 6 hrs after the infarction, when infarcted region appears blue and swollen.
- These changes explain the need for intervention within the first 4 to 6 hours of symptoms onset!!!


What happens after 48 hours of an MI?

Afters 48 hours, the infected area turns gray with yellow streaks as neutrophils invade the tissue and begin to remove the new products cell


What happens by 8 to 10 days after infarction?

Granulation tissue forms at the edge of the necrotic tissue


What happens over 2 to 3 months?

- The necrotic area eventually develops into a shrunken, thin, firm scar
- Scar tissue permanently change is the size and shape of the entire left ventricle, called ventricular remodeling.


Ventricular Remodeling Definition:

Decreases and causes what?

- Scar tissue that permanently CHANGES the size and shape of the entire left ventricle

- Remodeling may decrease left ventricular function, cause heart failure, and increase morbidity and mortality


Scarred tissue on the heart:

*HINT: Fails to do something

Scarred tissue does not contract, nor does it conduct electrically.
Thus this area is often the cause of chronic ventricular dysrhythmias surrounding the infarcted zone


Obstruction of the left anterior descending (LAD) artery causes what?

- Causes anterior or septal MIs because it perfuses the anterior wall and most of the septum of the left ventricle.
- Also causes PVCs/third degree heart block (Ig part left vent. involved)
- Patients with anterior wall MIs (AWMIs) have the highest mortality rate b/c they are most likely to have left ventricular failure and dysrhythmias from damage to the left ventricular


What does the circumflex artery supply?

The lateral wall of the left ventricle and possibly portions of the posterior wall or the sinoatrial (SA) and atrioventricular (AV) nodes.


What may the pt experience with an obstruction of the circumflex artery?

May experience a posterior wall MI (PWMI) or a lateral wall MI (LWMI) and sinus dysrhythmias


In most people, the right coronary artery (RCA) supplies what?

The SA and AV nodes, as well as the right ventricle and inferior or diaphragmatic portion of the left ventricle.


Pts with obstruction of the RCA often have what?
Causes damage where in the heart?
Nurse should obtain what?

- Have inferior wall MIs (IWMIs)
- About half of all inferior wall MIs are associated w/ an occlusion of the RCA, causing significant damage to the right ventricle
- Thus it is important to obtain a “right-sided” ECG to assess for right ventricular involvement


When are dysrhythmias treated?

When they cause hemodynamic compromise, increase myocardial oxygen requirements, or predispose the pt to lethal ventricular dysrhythmias


How will a pt w/ an inferior ACS present?
Nurse should monitor what?
If pt becomes hemodynamically unstable, what can be used?

- Bradycardia and second-degree atrioventricular (AV) blocks resulting from ischemia of the AV node.
- Rhythms tend to be intermittent
- Monitor cardiac rhythm and rate and the hemodynamic status
- If pt becomes hemodynamically unstable, a temporary pacemaker may be necessary


Pts w/ anterior ACS are likely to exhibit what?
What is a serious complication in this pt? Health care provider may insert what?
What should the nurse observe for?

- Premature Ventricular Contractions (PVCs) caused by ventricular irritability
- Third-degree or bundle branch block b/c it indicates that a large portion of the left ventricle is involved. Health care provider may insert a pacemaker. Observe pt closely to detect the development of HF.


Preventions of CAD:

- Smoking
- Diet
- Cholesterol
- Exercise
- DM
- Obesity


Risk Factors for Metabolic Syndrome:

- Pts who have 3 or more of these factors are diagnosed w/ metabolic syndrome
- HTN (B/P of 130/85 mm Hg or higher OR taking antihypertensive drugs)
- Decreased HDL levels, usually w/ high LDL (HDL <45 for men or <55 for women OR taking anticholesterol drugs)
- Increased lvl of triglycerides (Either 160 mg/dL or higher for men or 135 for women)
- Increased fasting blood glucose (Either 100 mg/dL or higher OR taking antidiabetic drugs)
- Large waist size ( 40 inches or greater for men or 35 inches or greater for women)


Sx of MI in women?

- Not always experience crushing chest pain
- Indigestion, burning, pressure
- Jaw pain
- Pain between shoulders


Atypical angina sx in women:

- Unusual fatigue
- Breaking out in cold sweats
- Sudden fatigue, NV, lightheadedness
- Anxiety, epigastric pain
- Usually NSTEMI


Inter professional collab care

- Assessment- hx, sx present delay this until stabilized
- Pain assessment
- B/P q hr, temp up after infarction-necrosis and inflamm response
- Heart rhythm and heart sounds
- S3 GALLOP- HF, serious complications of MI
- Peripheral pulses
- Skin temp
- Psych.- denial delays care, fear or anxiety
- Old people assess LOC FIRST!


Lab Assessment?

- Troponin T and I
- Chest x-ray not diagnostic for MI- CHF yes
- Thallium scans-radioisotope imaging to assess ischemia or necrotic muscle tissue related to angina or MI
- Contrast-enhanced cardiovascular magnetic resonance (CMR)
- 12-lead ECG- w/i 10 min of arrival (located location of ischemia/necrosis, STEMI, NSTEMI, abn. Q-wave signals myocardial necrosis)
- Echocardiogram - visualize heart structures
- ECG should be obtained w/i 10 min w/ pt w/ chest pain
- Cardiac catheterization - exact location of obstruction
- Computed tomography coronary angiography (CTCA)


Stress Test

- To determine oxygen demand
- If cannot exercise- Dobutamine


What to watch w/ stents?

- Watch for bleeding, hematomas - radial artery pressure dressing- radial/femoral artery- peripheral pulses!
- Distal to puncture- cap refill, warmth, sensation



Re-occlude 50% of the time- should not have chest pain post stent placement- ECG, VS, call the MD


Pain management

Nitro- Increases collateral blood flow/redistributes blood to subendocardium/dilates coronary arteries, decreases preload and afterload, no phosphodiesterase inhibitors w/i 24-48 hrs (pulmonary HTN), hold if under 100 SB/P

Morphine Sulfate- comfort/decreases 02 demand and relaxes muscles/decreases circulating catecholamines, watch SE-Narcan, 02 maintain >90%, semi Fowler’s, quiet environment


Drug Therapy

- ASA inhibits platelet aggregation/vasoconstriction Cher 325
- Glycoprotein (CP) llb/llla inhibitors-unstable angina/NSTEMI- watch for bleeding/hypersensitivity reactions
- Antiplatelet clopidogrel prevents platelet aggregation
- Beta blockers- decreases size of infarct/dysrhythmias
- ACE Inhibitors
- Reperfusion therapy
- Thrombolytic therapy-fibrinolytics-dissolve clot/restore blood flow
- Percutaneous coronary intervention- reopen coronary
- ST segment changes will resolve- ECG changes
- Heparin 3-5 days, and ASA or enoxaparin (LMWH)


Thrombolytic Therapy- Fibrinolytics

- Dissolve clot/restore blood flow
- W/i 6 hrs of even and 30 min of arrival to ED
- Watch for bleeding-OB stool, neuro changes- brain bleed, distended abdomen, H&H changes


What is the primary factor in the development of CAD?

Numerous risk factors, both nomodifiable and modifiable, contribute to atherosclerosis and subsequently to CAD


What is the most important risk factor for developing CAD in women?



Health promotion efforts are directed toward what?

Controlling or altering modifiable risk factors for CAD


Angina pain

Is ischemic pain, it usually improves when the imbalance between oxygen supply and demand is resolved

Rest reduces tissue demands, and nitroglycerin improves oxygen supply

Associated sx: N/V, diaphoresis, dizziness, weakness, palpitations, and SOB



- Substernal chest discomfort:
>Radiating to the left arm
>Precipitated by exertion or stress (or rest in variant angina)
>Relieved by nitroglycerin or rest
>Lasting less than 15 min.
- Few, if any, associated sx



- Pain or discomfort:
>Substernal chest pain/pressure radiating to the left arm
>Pain/discomfort in jaw, back, shoulder, or abdomen
>Occurring w/o cause, usually in the morning
>Relieved only by opioids
>Lasting 30 min or more
- Frequent associated sx:
>Feelings of fear and anxiety
>Epigastric distress
>Disorientation/acute confusion
>Feelings “SOB”


Assessment-Auscultate for?

S3 gallop, which often indicates HF- serious and common complication of MI

S3 heart sound is heard w/ the bell of the stethoscope over the apex of the heart



Temp elevation for several days after infarction

High as 102 F may occur in response to myocardial necrosis, indicating the inflammatory response


What is the normal right atrial pressure?

- 1 to 8 mm Hg
- Lower pressure: hypovolemia, adm. fluid bolus. Diuretics are contraindicated!!


What is a major complication related to intra-arterial blood pressure?

- Hemorrhage at the insertion site
- HR will increase while B/P decreases


What is a complication after coronary artery bypass graft surgery?

Hypertension which can be dangerous because it puts too much pressure on the suture line and causes bleeding


What does wide and large Q-waves indicated in a ECG?

- Pt had an MI in the past
- Results from MI and necrotic ventricular cells that do not conduct electrical impulses.


Contraindications to thrombolytic therapy (absolute):

-Any prior intracranial hemorrhage
-Known structural cerebral vascular lesion (arteriovenous malformations)
-Known malignant intracranial neoplasm (primary or metastatic)
-Ischemic stroke w/i 3 months EXCEPT acute ischemic stroke w/i 3 hr
-Suspected aortic dissection
-Active bleeding or bleeding diathesis (excluding menses)
-Significant closed-head or facial trauma w/i 3 months


Contraindications to thrombolytic therapy (Relative):

-Hx of chronic, severe, poorly controlled HTN
-Severe uncontrolled HTN on presentation (SBP >180 mm Hg or DBP >110)
-Hx of prior ischemic stroke w/i 3 months, dementia, or known intracranial pathology not covered in contraindications
-Trumatic or prolonged (equal or less than 10 min) CPR or major surgery (w/i 3 wks)
-Recent (w/i 2-4 wks) internal bleeding
-Non-compressible vascular punctures
-For streptokinase/anistreplase: prior exposure (>5 days ago) or prior allergic reaction to these agents
-Active peptic ulcer
-Current use of anticoagulants; the higher the INR, the higher risk for bleeding


What should the nurse give to reduce the risk of complications with thrombolytic therapy?

IV or low-molecular-weight Heparin and Aspirin are prescribed b/c large amounts of thrombin are released, increasing risk of vessel reocclusion