Myocardial Infarction Flashcards
What’s the difference between Unstable Angina, STEMI, and NSTEMI?
- whether the ischemia is severe enough to cause heart muscle injury and release cardiac biomarkers
- Unstable Angina: Chest pain without heart muscle damage; no cardiac biomarkers in the blood
- NSTEMI: Chest pain with heart muscle damage; cardiac biomarkers (like troponin) are elevated in the blood
- STEMI: Chest pain with significant heart muscle damage; elevated cardiac biomarkers and ST-segment elevation on ECG.
Why does necrosis occur with MI?
Necrosis is caused by ischemia, but decreased blood flow plays a part.
The problem is O2!
What’s the difference between Transmural and Subendothelial infarct?
- Transmural Infarct: MI affects the full thickness of the heart muscle (complete blockage of an artery); more severe damage
- Subendothelial Infarct: MI affects the inner one third of the heart muscle (narrowed arteries); less damage
transmural affects the whole muscle wall, while subendothelial affects just the inner part of the muscle
Describe the three zones of tissue damage.
- myocardial tissue that becomes necrotic
- surrounding zone of injured cells (recoverable)
- outer zone in which cells are ischemic (blood flow needs to be re-established to be salvaged)
What could happen if treatment for the zones of tissue damage is delayed?
may progress to necrosis, increasing the size of the infarct, damaging more heart muscle
What are risk factors of MI?
- age/genetics
- lipid levels
- tobacco
- ↓ estrogen which is cardioprotective
- stress
- blood pressure
- inactivity
- obesity - BMI > 30
- > 40 men (waist circumference)
- > 35 women (waist circumference)
- ↑ cholesterol
Describe the different types of cholesterol. What are good cholesterol level values for each?
total, HDL, LDL
- Total cholesterol: sum of HDL and LDL
- HDL: helps bad fat leave the body; helps absorb good fats (good cholesterol)
- LDL: builds up in arteries and causes plaque (bad cholesterol)
- Total cholesterol <200 mg/dl
- HDL >50 mg/dl
- LDL <100 mg/dl
What are clinical manifestations of MI?
- spontaneous chest pain not relieved by rest or NTG
- lower sternal region and the upper abdomen
- pain increases steadily
- pain is heavy and radiates to other parts of the body
- described as tightness, burning, pressure, or indigestion
-
fatal arrhythmias
- ex: V-Fib - heart is just quivering, not contracting
What is usually accompanied with the pain during MI?
- shortness of breath - ↓O2
- pallor - ↓CO
- diaphoresis
- dizziness - ↓CO
- lightheadedness - ↓CO
- nausea and vomiting - vagal stimulation
How does pain differ for women during MI?
- 50% of women with an MI do not complain of chest pain.
- SOB
- nausea/vomiting
- jaw/back pain
not razzle dazzle
How does pain differ for older adults during MI?
confusion or disorientation due to decreased cardiac output
What are the ECG changes during MI?
- ST-segment elevation
- Q wave prolongation
- T wave inversion
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What cardiac biomarkers are present and elevated during MI?
- Troponin – primary biomarker for myocardial infarction
- Begin to rise within 3 hours and may remain 7-10 days.
- Creatine-Kinase (MB) – enzyme found in heart muscle
- rise within 4-8 hours and decline to normal limits in 2-3 days
elevated when heart muscle is damaged (leaks into bloodstream)
How can you explain cardiac stress test to patient?
“We’ll have you either walk on a treadmill or receive medication to increase your heart rate, simulating the effect of exercise. During this time, we’ll monitor your heart’s activity with an ECG and possibly take imaging to see how well blood flows through your heart. This test helps us find any blockages or areas where blood flow might be restricted.”
evaluates how well the heart works under stress or physical exertion
not razzle dazzle
What is the purpose of a cardiac catheterization?
- Uses dye to provide images of the coronary circulation
- Identifies the location and severity of any blockages
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What are the nursing implications for Cardiac Catheterization?
- Fasting: Patient must fast for 4-8 hours before the procedure.
- Contrast Dye: Expect a warm, flushed sensation when the dye is injected, lasting 10-15 seconds.
- Coughing: Patient may cough when the catheter enters the pulmonary artery.
- Post-Procedure: Bedrest for 4-8 hours; keep extremity extended and immobilized with sandbags to prevent bleeding.
- Monitoring: Check pulses, color, and sensation in both extremities.
- Hydration: Increase fluid intake to help flush out the contrast dye.
maybe just hard read, not razzle dazzle
How will the O2 be administered?
Nasal cannula = goes straight into the body
- usually not an oxygen mask because there is O2 around their face that isn’t going into the body
- putting a mask on might make them feel smothered
Implications for oxygen therapy if patient has chronic respiratory condition (COPD/Asthma)?
- They do not need as much O2 (no more than 2L)
- Their breathing is initiated by CO2
What is the drug of choice when a patient is experiencing an MI?
Intravenous Nitroglycerin
What are two side effects that could occur from NTG?
- low blood pressure
- NTG is a vasodilator
- headache
- due to widening of vessels in the head
not razzle dazzle
What are anticoagulants and antiplatelets used for?
To prevent clot formation
What do thrombolytics do?
Dissolves any thrombus that may have formed in the coronary artery (clot busters)
Based on the actions of the antiplatelets, anticoagulants, and thrombolytics, what is a major side effect that could occur?
- uncontrolled bleeding
- ↓ H&H
- ↓ platelets
- ↑ INR
What are three reasons morphine is given?
- nitrates and oxygen are ineffective in relieving pain
- relieves pain
- relaxes smooth muscle and decreasing circulating catecholamines (stress hormones that overwork the heart)
What is the purpose of a percutaneous coronary intervention (stent)? Possible side effects?
- non-surgical procedure
- places a small structure (a stent) in the heart using a catheter
- opens up blood vessels in the heart
possible side effects: bleeding and infection
not razzle dazzle
What is the purpose of a coronary artery bypass graft?
- surgical procedure
- placing a blood vessel graft between the aorta and the affected artery in the heart
- creates a new path for blood to go around a blocked or narrowed artery
extra blood vessel can come from leg, chest, or arm
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