Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

3: MED1 Y3 - Cardiovascular [2] > [3] Acute Myocardial Infarction REDO > Flashcards

[3] Acute Myocardial Infarction REDO Flashcards

1
Q

What happens in a myocardial infarction?

A

A complete occlusion of a coronary vessel, leading to infarct (death) of the myocardium it supplies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What causes a complete occlusion of a coronary vessel?

A

The fibrous cap of the atheromatous plaque undergoes erosion or fissuring, exposing blood to the thrombogenic material in the necrotic core. This results in a platelet ‘clot’ followed by a fibrin thrombus, which can either occlude the entire vessel where it forms, or break off to form an embolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the causes of a myocardial infarction?

A
  • Coronary heart disease
  • Drug misuse, e.g. cocaine, amphetamides, methamphetamies
  • Hypoxia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the symptoms of a myocardial infarction?

A
  • Chest pain, which may radiate to the jaw, neck, arms, and back
  • Shortness of breath
  • Feeling weak and/or lightheaded
  • Overwhelming feeling of anxiety
  • Autonomic features, such as sweating, pallor, nausea, and vomiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the chest pain like in a myocardial infarction?

A

Typical ischaemic chest pain, that is very severe, persistent at rest, and often no precipitatnt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Where is ischaemic chest pain felt?

A

It can be central, retrosternal, or left sided. It may radiate to the shoulders and arms, with the left side being more common than the right, as well as the neck, jaw, epigastrum, and back

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is the nature of ischaemic chest pain described?

A

As tightening, crushing, constriction, or pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Is the chest pain in myocardial infarction relieved by rest?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is a myocardial investigation investigated?

A
  • ECG
  • Blood tests to look for cardiac troponin and creatine kinase
  • Chest x-ray
  • Echocardiogram
  • Coronary angiography
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the functions of ECG investigations in a patient with a suspected myocardial infarction?

A
  • Confirm diagnosis of MI
  • Determine what type of MI was experienced
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Why is it important to determine what kind of MI a patient has experienced?

A

To determine the best treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can MIs be classified into?

A

STEMI or NSTEMI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is more serious, a STEMI or NSTEMI?

A

STEMI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens in a STEMI?

A

There is prolonged interruption to the blood supply, caused by a total blockage of a coronary artery. This can cause extensive damage to a large area of the heart, and the damage extends through the full thickness of the myocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How can a STEMI be differentiated from a NSTEMI?

A

ECG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How does a STEMI appear on ECG?

A

It has ST elevation in 2 or more leads facing the same area, of at least 1mm in limb leads, or 2mm in chest leads. There will also be a new left bundle branch block

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens to the ECG minutes to hours after a STEMI heart attack?

A

ST elevation, with T wave upright

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens to the ECG hours to a half a day after an STEMI?

A
  • ST elevation
  • Decreasing T wave
  • Decreasing R wave
  • Q wave begins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to the ECG 1-2 days after STEMI?

A

Q wave deepens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What happens to the ECG a few days after a STEMI?

A
  • ST normalises
  • T wave is inverted
  • Q wave persists
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens to the ECG a few weeks after a STEMI?

A
  • ST and T normal
  • Q waves persist
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why is an NSTEMI less serious than a STEMI?

A

Because the supply of blood to the heart is only partially blocked, and therefore a smaller section of the heart is damaged, and the damage does not extend the full thickness of the myocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How is an NSTEMI differentiated from unstable angina?

A

Measurement of blood troponin - troponin is present in the blood with an NSTEMI, but not unstable angina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are Acute Coronary Syndromes (ACS)?

A

A group of symptoms attributed to the obstruction of the coronary arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the types of ACS?
* Unstable angina * NSTEMI * STEMI
26
What is unstable angina?
When there is serious restriction to blood flow to the heart, but no pernament damage
27
Why is unstable angina considered to be a medical emergency?
Due to the possibility of progression to serious heart damage, or a STEMI
28
What is the goal of treatment of unstable angina?
Prevent it from progressing to MI, and limiting muscle loss in MI
29
How can an ECG be used to localise the vessel that is blocked in an MI?
The abnormality will be seen in the lead facing the infarcted, dead myocardium, and so to determine, you should look at the lead in which the abnormality is found
30
What are cardiac troponin I (cTnI) and T (cTnT)?
Both proteins important in actin/myosin interactions
31
When are cTnI and cTnT released?
In myocyte death, *as occurs during a myocardial infarction*
32
When will cardiac troponins be found in the blood following an MI?
They rise 3-4 hours after the first onset of pain, and peak at 18-36 hours. They then decline slowly for 10-14 days
33
What is the advantage of the use of cardiac troponins clinically?
They are a very sensitive and specific biomarker
34
What is creatine kinase?
An iso-enzyme found in the heart, as well as skeletal muscle and the brain
35
What is the cardiac isoform of creatine kinase?
CK-MB
36
What does the presence of CK-MB in the blood indicate?
A myocardial infarction has occured
37
When will CK-MB be found in the blood after an MI?
First rises 3-8 hours after onset, and peaks at 24 hours
38
Why might a chest x-ray be useful in MI?
To rule out other causes of symptoms, and check for complications that might arise as a result of MI, e.g. pulmonary oedema
39
What is an echocardiogram?
A sonogram of the heart that uses sound waves to build up a picture of the internals of the heart
40
What information about the heart can an echo provide?
* Size and shape of heart * Pumping capacity * Location and extent of any tissue damage
41
What is the application of an echocardiogram in a MI?
It identifies exactly what area of the heart is damaged, and how that damage has affected the functioning of the heart
42
What is the use of coronary angiography in MIs?
It is used to determine if a blockage or narrowing has occured in the coronary arteries, and if so, where
43
What does the coronary angiography procedure involve?
Inserting a catheter into a blood vessel in the groin or arm, and then guiding it using x-rays into the coronary arteries. Contrast is then pumped through the catheter, and visualised using an x-ray to see how it flows through the coronary arteries, and determine the site of blockage or narrowing
44
What is involved in the emergency treatment of a STEMI?
1. Attach ECG monitor and record 12 lead ECG 2. Obtain IV access and take bloods 3. Perform a brief assessment 4. Give aspirin and clopidogrel 5. Morphine and anti-emetic 6. If PCI is available within 120 minutes, perform primary PCI. If not, fibrinolysis
45
What bloods should be taken during the immediate management of STEMI?
* FBC * U&E * Glucose * Lipids * Troponin
46
What should the brief assessment include in the immediate management of STEMI?
* History of CVD disease and risk factors for IHD * Examination * CXR if it will not delay treatment * Information about any contraindications to fibrinoylsis or PCI
47
What should be looked for on examination in STEMI?
* Pulse * BP in both arms * JVP * Murmurs * Signs of CCF * Upper limb pulses * Scars from previous cardiac surgery
48
What dose of aspirin should be given in the immediate management of STEMI?
300mg PO
49
What dose of clopidogrel should be given in the immediate management of a STEMI?
300mg PO
50
What dose of morphine should be given in the immediate management of a STEMI?
5-10mg IV
51
Give an example of an anti-emetic that can be given alongside morphine in the immediate management of a STEMI?
Metoclopramide 10mg IV
52
What is aspirin?
A weak organic acid
53
How is aspirin unique among the NSAIDs?
It irreversibly acetylates, and thus inactivates, cyclooxygenase
54
How do low doses of aspirin prevent platelet aggregation?
They irreversibly inhibit thromboxane production via the acetylation of cyclooxygenase, thus stopping thromboxanes action of platelet aggregation
55
How long does decreased platelet aggregation due to aspirin last?
3-7 days
56
Why does decreased platelet aggregation due to aspirin last for 5-7 days?
Because platelets lack nuclei, and so they cannot synthesise new enzyme, so the lack of thromboxane persists for the lifetime of the platelet
57
What are the most common side effects of aspirin?
* Indigestion and epigastric pain * Bleeding and bruising
58
What are the uncommon and rare side effects of aspirin?
* Hives * Tinnitus * Difficulty breathing * Allergic reations * Haemorrhage
59
What are the pharmacokinetics of aspirin dependant on?
Dose
60
What are the pharmacokinetics of aspirin in low doses (such as in STEMI)?
It shows first order kinetics with a half life of 4 hours
61
What is considered to be 'higher doses' of aspirin?
12x300mg/day
62
What are the pharmacokinetics of aspirin at high doses?
Zero order kinetics
63
How is aspirin metabolised at cardiac doses?
It is hydrolysed to salicylate and acetic acid by esterases in the tissues and blood
64
What hapepns to salicyate in the body?
It is converted by the liver to water soluble conjugates that are rapidly cleared by the kidney
65
Why should aspirin be avoided in patients with gout?
Because salicylate is secreted into the urine, and can affect uric acid secretion
66
What is the mechanism of action of clopidogrel?
It irreversibly inhibits the binding of ADP to its receptors on platelets, and thereby inhibits the activation of GP IIb/IIIa receptors required for platelets to bind to fibrinogen and each other
67
What are the common side effects of clopidogrel?
* Bleeding * Nosebleeds * Diarrhoea * Abdominal pain * Indigestion * Increased bleeding from wounds
68
What are the serious side effects of clopidogrel?
* Severe bleeding or pain * Haematemesis * Haematuria or blood in stool * Allergic reaction
69
What are the cautions and contraindications to clopidogrel?
* Active stomach ulcer, or stomach ulcer in past * Brain haemorrhage * Haemophilia, or other bleeding disorder * Liver or kidney problems * Previous allergic reactions to medication * Pregnant or breastfeeding
70
What is the problem with taking other drugs alongside clopidogrel?
It can affect its efficacy, or increase the changes of getting side effects
71
What drugs might interact with clopidogrel?
* Aspirin (may be recommended theyrre together together anyway) * NSAIDs * Anticoagulants such as warfarin * Other types of antiplatelets such as dipyridamole * SSRIs * PPIs
72
Is clopidogrel bound to plasma proteins?
Yes, extensively
73
Describe the metabolism of clopidogrel?
It undergoes hepatic metabolism by cytochrome P450 enzymes to active metabolites
74
How long does it take to reach the maximum effect of clopidogrel?
3-5 days
75
What happens when clopidogrel is suspended?
The platelet system needs time to recover
76
How does elimination of clopidogrel and its metabolites occur?
Faecal and renal routes

3: MED1 Y3 - Cardiovascular [2] (19 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions