Myocardial Infarction - STEMI and NSTEMI Flashcards
Acute coronary syndrome (ACS) is usually the result of a thrombus from an atherosclerotic plaque blocking a coronary artery. When a thrombus forms in a fast-flowing artery, it is formed mainly of platelets. This is why antiplatelet medications such as aspirin, clopidogrel and ticagrelor are the mainstay of treatment.
There are three types of acute coronary syndrome:
Unstable angina
ST-elevation myocardial infarction (STEMI)
Non-ST-elevation myocardial infarction (NSTEMI). What is the incidence of ACS?
1 - 2 cases per 100,000
2 - 20 cases per 100,000
3 - 200 cases per 100,000
4 - 2000 cases per 100,000
3 - 200 cases per 100,000
More common in men
STEMI is the most common of the 3
What age does the incidence of acute coronary syndrome peak at?
1 - 40-50
2 - 50-60
3 - 60-70
4 - >75
3 - 60-70
Acute coronary syndrome is a condition that develops over a number of years. Which of the following is a risk factor that can be modified?
1 - Increasing age
2 - Male gender
3 - Diabetes
4 - Family history
3 - Diabetes
Acute coronary syndrome is a condition that develops over a number of years. Which of the following is risk factors that cannot be modified?
1 - Increasing age
2 - Smoking
3 - Diabetes mellitus
4 - Hypertension
5 - Hypercholesterolaemia
6 - Obesity
1 - Increasing age
Acute coronary syndrome (ACS) generally develops in patients who have ischaemic heart disease (IHD), a term synonymous ACS. It describes the gradually build up of fatty plaques within the walls of the coronary arteries. This leads to two main problems:
1 - Gradual narrowing =
- less blood and oxygen reaching the myocardium
- exertion increases blood and oxygen demand that myocardium cannot provide
- angina presents as chest pain due to lack of oxygen reaching the myocardium
2 - Risk of sudden plaque rupture =
- fatty plaques build up in the endothelium
- increased risk of rupture that can lead to rupture and sudden occlusion of the artery
- occlusion means no blood/oxygen reaches that specific part of the myocardium.
What is the earliest stage of atherogenosis (atherosclerotic plaque formation, leading to coronary artery heart disease)?
1 - fatty streaks
2 - LDL infiltration
3 - cytokine release
4 - foam cells build up
1 - fatty streaks
Coronary atherosclerosis is a complex inflammatory process. Although the exact cause is unknown, the trigger id commonly linked with damage and/or dysfunction to the epithelium of blood vessels. Which of the following has not been identified as a trigger causing epithelium damage and/or dysfunction?
1 - morbid hypertension
2 - biochemical abnormalities (LDL)
3 - diabetes mellitus
4 -immunological factors (free radicals from smoking)
5 - inflammation
6 - genetic alteration
7 - biochemical abnormalities (HDL)
7 - biochemical abnormalities (HDL)
Following the initial damage/dysfunction to blood vessel epithelium, what is the first things that occurs leading to coronary atherosclerosis?
1 - increased cytokine expression
2 - foam cells build up
3 - LDL cross epithelium
4 - macrophages phagocytose LDL through oxidation
3 - LDL cross epithelium
Following the initial damage/dysfunction to blood vessel epithelium, LDL cross the epithelium. What then occurs leading to coronary atherosclerosis?
1 - increased cytokine expression
2 - foam cells build up
3 - LDL cross epithelium
4 - macrophages phagocytose LDL through oxidation
4 - macrophages phagocytose LDL through oxidation
- macrophages cross endothelium to get to LDLs
Following the initial damage/dysfunction to blood vessel epithelium, we have dead macrophages full of LDLs, called foam cells. What is the next thing that occurs leading to coronary atherosclerosis?
1 - increased cytokine expression
2 - foam cells build up
3 - LDL cross epithelium
4 - macrophages phagocytose LDL through oxidation
2 - foam cells build up
- foam cells are macrophages that have died and begin secreting cytokines
- attract more monocytes to area
What is a fatty streak, which is a term used in atherosclerosis?
1 - build up of HDL beneath epithelium
2 - build up of LDL beneath epithelium
3 - build up of foam cells beneath epithelium
4 - build up of macrophages beneath epithelium
3 - build up of foam cells beneath epithelium
Fatty streaks can occur in any patients throughout their life. Why are fatty streaks dangerous?
1 - thrombogenic
2 - increase blood pressure
3 - increase cytokine release
4 - decrease HDL levels
1 - thrombogenic
- susceptible to blood clotting on it
Fatty streaks formed by dead macrophages containing LDL are thrombogenic, meaning they are susceptible to blood clotting. This causes the release of platelet derived growth factor, and then smooth muscle migration and proliferation to the tunica intima from the tunica media. Smooth muscle cells then secretes things that become the fibrous cap. Which of the following is NOT a component of the fibrous cap?
1 - collagen
2 - elastin fibrous cells
3 - elastic cartilage
4 - proteoglycans
3 - elastic cartilage
- purpose of the fibrous cap is to prevent blood clotting
Together the fibrous cap and fatty streak are called what?
1 - thrombosis
2 - embolus
3 - atheroma
4 - plaque
4 - plaque
In addition to secreting the contents that make up the fibrous cap, what else do smooth muscle cells secrete in the fatty streak?
1 - Ca2+
2 - Na+
3 - Mg+
4 - Cl-
1 - Ca2+
- normally deposited into vessel walls by LDL
- cholesterol crystals are also present
In addition to secreting the contents that make up the fibrous cap, smooth muscle cells secrete Ca2+ into the fatty streak, which is normally deposited into the vessel walls by LDL. Normally what then removes the Ca2+ to stop the hardening of blood vessel walls?
1 - lipoprotein lipase
2 - HDL
3 - VLDL
4 - albumin
2 - HDL
- plaques impair HDLs ability to remove Ca2+
Once Ca2+ has been deposited into the fatty streak and vessel walls, do the vessel walls become more elastic or stiff?
- stiff due to Ca2+ forming crystals
What generally causes a myocardial infarction that has been in the arteries for some time?
1 - low nitrates
2 - increased Na+ and K+
3 - fibrous cap of plaque becomes unstable and ruptures
4 - endothelium become damaged and leak collagen
3 - fibrous cap of plaque becomes unstable and ruptures
- rupture is due to thinning of the cap and core expansion
- thrombogenic contents (foam cells) of plaque leak out causing blood clot
During the rupture of fibrous cap or the expansion of a plaque, what % of blood vessel occlusion can lead to stenosis and lead to ischaemia given any increase in O2 demand?
1 - 10%
2 - 30%
3 - 50%
4 - 70%
3 - 50%
- 50% reduction in luminal diameter causes a 70% reduction in luminal cross-sectional area
As fatty streaks form in the endothelium, platelets bind to damaged epithelium. They then release platelet derived growth factor that drives the development of what?
1 - more macrophages migrate to the area
2 - lymphocytes are activated
3 - smooth muscle cell proliferation
4 - increased cytokine secretion from fatty streak
3 - smooth muscle cell proliferation
- smooth muscle cells move from tunica media to tunica intima
When plaques rupture, what is the primary content that is very atherogenic that leaks out causing the formation of red thrombus?
1 - collagen
2 - Ca2+
3 - foam cells
4 - smooth muscle cells
3 - foam cells
- thrombus is blood clot
- embolism is clot moving in blood
Once a plaque ruptures a red thrombus is formed. This thrombus may cause the following:
- occlusion of the artery
- partial occlusion of the artery
- embolise distally
- plaque progression
Match the above with the following: ST elevated MI, Non-ST elevation MI, stable angina and unstable angina:
- ST elevated MI = occlusion of the artery
- Non-ST elevation MI = partial occlusion of the artery
- stable angina = embolise distally
- unstable angina = plaque progression
Which of the following is a typical clinical feature of a patient presenting with acute coronary syndrome?
1 - left sided chest pain (pressure, tightness, or crushing sensation)
2 - radiating pain to the left arm, jaw, or neck
3 - dyspnoea
4 - nausea and vomiting
5 - sweating (response to pain)
6 - palpitations
7 - all of the above
7 - all of the above
Patients may also appear anxious, restless, or diaphoretic due to sympathetic activation.
Cyanosis may be present in severe cases, indicating hypoxia.
Which of the following would be recognised as atypical symptoms of an acute coronary syndrome?
1 - epigastric pain
2 - fatigue
3 - syncope or pre-syncope
4 - all of the above
4 - all of the above
When examining a patient with suspected acute coronary syndrome (ACS), all of the following may present for at least 15 minutes, but which is least likely?
1 - Hypertension
2 - Tachycardia
3 - Tachypnoea
4 - Reduced oxygen saturations
1 - Hypertension
Hypotension is more common and may indicate cardiogenic shock, whereas hypertension may reflect a stress response.
Bradycardia may be present in inferior myocardial infarction due to vagal activation.
In an acute occlusion of the coronary arteries we may see an STEMI. Which of the following are key features we would be able to detect in the >1hour on an ECG?
1 - wide T waves
2 - tall T waves
3 - ST elevation
4 - all of the above
4 - all of the above
STEMI criteria are clinical symptoms consistent with ACS ≥ 20 minutes duration with ECG features in ≥ 2 contiguous leads.
STEMI and LBBB are key features
Which 2 of the following features are key in a NSTEMI?
1 - narrow T waves
2 - ST depression
3 - T wave inversion
4 - missing P waves
2 - ST depression
3 - T wave inversion
In an acute occlusion of the coronary arteries we may see an STEMI. Which of the following are key features we would be able to detect in 6 hours to months on an ECG?
1 - wide Q waves
2 - T wave inversion
3 - ST returns to normal
4 - all of the above
4 - all of the above
In a STEMI and NSTEMI are troponin levels raised?
- yes
BUT NOT needed to diagnose STEMI as the ECG is good enough for this.
Used to distinguish NSTEM from unstable angina. Measured immediately and 3h from symptom onset. An increase indicates myocardial damage.
What are the two major coronary arteries coming from the main left coronary artery?
1 - left circumflex and left anterior descending artery
2 - left circumflex and right coronary artery
3 - right coronary artery and conus artery
4 - conus artery and left circumflex
1 - left circumflex and left anterior descending artery
- left circumflex supplies 20-30% of blood to heart
- left anterior descending artery supplies 45% of blood to heart
- in total they supply up to 70% of blood to heart so VERY HIGH RISK lesions
- described as the widowmaker if there is an MI here
What are the major coronary arteries coming from the main right coronary artery?
1 - left circumflex
2 - right coronary artery
3 - conus artery
4 - right circumflex
2 - right coronary artery
- supplies 25-30% of blood to the heart
Which of the following coronary arteries is most dangerous if blocked?
1 - left anterior descending artery
2 - left circumflex artery
3 - right coronary artery
4 - conus artery
1 - left anterior descending artery
- supplies over 45% of blood to heart, so if blocked has a major effect
Which blood vessels provides the majority of the blood to the antero-septal part of the heart?
1 - left anterior descending artery
2 - left circumflex artery
3 - right coronary artery
4 - proximal left anterior descending
5 - coronary
1 - left anterior descending artery
Infarct here would be detected on V1-V4
Which blood vessels provides the majority of the blood to the posterior part of the heart?
1 - left anterior descending artery
2 - left circumflex artery
3 - right coronary artery
4 - proximal left anterior descending
5 - coronary
2 - left circumflex artery
Coronary artery also provides blood
Infarct here would be detected on V1-V3
Remember posteRioR has 2 tall R waves
Which blood vessels provides the majority of the blood to the inferior part of the heart?
1 - left anterior descending artery
2 - left circumflex artery
3 - right coronary artery
4 - proximal left anterior descending
5 - right coronary
5 - right coronary
Infarct here would be detected on II, III, and aVF
Which blood vessels provides the majority of the blood to the lateral part of the heart?
1 - left anterior descending artery
2 - left circumflex artery
3 - right coronary artery
4 - proximal left anterior descending
5 - coronary
2 - left circumflex artery
Infarct here would be detected on I, aVL +/- V5-6
Remember I and aVL are on one side and V5 and V6 are on the other side, similar to house the left circumflex wraps around the heart
Which blood vessels provides the majority of the blood to the antero-lateral part of the heart?
1 - left anterior descending artery
2 - left circumflex artery
3 - right coronary artery
4 - proximal left anterior descending
5 - coronary
4 - proximal left anterior descending
Infarct here would be detected on V1-6, I, aVL
Leads V1-V4 supply which part of the heart?
1 - antero-septal
2 - inferior
3 - antero-lateral
4 - lateral
5 - posterior
1 - antero-septal
Changes in leads V1-V3 supply which part of the heart?
1 - antero-septal
2 - inferior
3 - antero-lateral
4 - lateral
5 - posterior
5 - posterior
Changes in leads I, aVL +/- V5-6 supply which part of the heart?
1 - antero-septal
2 - inferior
3 - antero-lateral
4 - lateral
5 - posterior
4 - lateral
Changes in II, III, aVF supply which part of the heart?
1 - antero-septal
2 - inferior
3 - antero-lateral
4 - lateral
5 - posterior
2 - inferior
Changes in V1-6, I, aVL supply which part of the heart?
1 - antero-septal
2 - inferior
3 - antero-lateral
4 - lateral
5 - posterior
3 - antero-lateral
A new diagnosis of which of the following is also indicative of acute coronary syndrome?
1 - right bundle branch block
2 - left bundle branch block
3 - atrial fibrillation
4 - atrial flutter
2 - left bundle branch block
- If present it is always pathological
All of the following should be considered in a patient presenting with an MI, but which is least likely of these?
1 - Aortic Dissection
2 - Gastro-Oesophageal Reflux Disease (GORD)
3 - Pulmonary Embolism
4 - Cholecystitis
4 - Cholecystitis
Which 2 of the following are the 1st line investigations in a patient with suspected MI?
1 - echocardiogram
2 - troponin
3 - ECG
4 - creatine kinase MB
5 - chest X-ray
2 - troponin
Measured immediately and 3h from symptom onset. An increase indicates myocardial damage. A rise, rules out unstable angina
3 - ECG
Echocardiogram gives information about the left ventricle, wall anomalies or other pathology
Chest X-ray to rule out other differentials
Does a raised troponin and ST changes on an ECG always lead to a coronary obstruction?
- No
This can be referred to as Myocardial infarction with non-obstructive coronary arteries (MINOCA). A type of heart attack that occurs when the heart’s blood flow is poor, but the coronary arteries are normal or near-normal.
Causes can be seen in the figure
Which of the following scoring systems is used to help guide the severity of the acute coronary syndrome and guide management?
1 - CURB65
2 - WELLS2
3 - CHA2DS2-VASc
4 - GRACE
4 - GRACE
Takes into account age, vital signs, kidney function, cardiac markers among others.
GRACE score helps guide the management of patients with acute coronary syndrome. Patients with a score above what would be considered for Coronary Angiography, which may lead to percutaneous coronary intervention?
1 - >1%
2 - >3%
3 - >10%
4 - >20%
2 - >3%
> 3% = moderate to high risk of 6-month probability of death
<3% = low risk of 6-month probability of death
STEMI almost always PCI
NSTEMI PCI if GRACE score >3%
If a patient presents with symptoms of acute coronary syndrome (ACS) we must perform the following as soon as possible:
- bloods (troponin)
- ECG
- risk scoring (GRACE score)
In addition, patients should be treated with which 4 of the following?
1 - aspirin 300mg
2 - IV morphine
3 - nitrates
4 - enoxaparin
5 - oxygen
1 - aspirin 300mg
2 - IV morphine
3 - nitrates (GTN spray)
5 - oxygen (ONLY IF SATS <94%)
GTN is a vasodilator and can cause a drop in BP and syncope
Fondaparinux may be given as an anti-thrombin therapy in NSTEMI and unstable angina, BUT NOT in STEMI
Which of the following treatments has been shown to have the greatest reduction in 30 day mortality in the options below?
1 - Aspirin
2 - Coronary angiography
3 - GTN infusion
4 - Ticagrelor
5 - TPA (tissue plasminogen activator; “thrombolysis”)
2 - Coronary angiography
If a patient has a confirmed diagnosis of a STEMI and symptoms for <12 hours, they should be offered Angiography with follow-on primary PCI in what time frame from arriving at the hospital?
1 - <30 minutes
2 - <60 minutes
3 - <120 minutes
4 - <360 minutes
3 - <120 minutes
Typically given aspirin and prasugrel in preparation for the PCI
If a patient presents with a STEMI and has a GRACE score >3%, but they are unable to receive angiography with follow-on primary PCI in <120 minutes they should be offered fibrinolysis. Which of the following medication should typically be given as a fibrinolysis?
1 - Tranexamic acid
2 - Fondaparinux
3 - Alteplase
4 - Ticagrelor
3 - Alteplase
Alteplase converts plasminogen to the proteolytic enzyme plasmin, which lyses fibrin as well as fibrinogen.
If a patient presents with a NSTEMI and has a GRACE score >3%, how soon should they have angiography, with a potential follow up for percutaneous coronary intervention?
1 - >12h
2 - <72h
3 - <7 days
4 - >14 days
2 - <72h
In addition to performing PCI in a NSTEMI (based on the GRACE score), patients should also be treated with all of the following, EXCEPT which drug?
1 - Aspirin 300mg stat dose
2 - Ticagrelor 180mg
3 - Oxygen
4 - Morphine
5 - Antithrombin (fondaparinux)
6 - Nitrate (GTN)
3 - Oxygen
Only given if sats <94%
Use BATMAN mnemonic
Following the initial presentation, a patient will be advised about lifestyle changes. They will also be placed on all of the following medications as part of secondary prevention, EXCEPT which one?
1 - Bisoprolol titrated to max dose
2 - Doxazosin 15mg OD
3 - Dual anti-platelet therapy (aspirin and ticagrelor)
4 - Atorvastain 80mg OD
5 - Ramipril titrated to max dose
2 - Doxazosin 15mg
Can be atenolol or Bisoprolol
Aspirin 75mg once daily indefinitely
Another Antiplatelet (e.g., ticagrelor or clopidogrel) for 12 months
Atorvastatin 80mg once daily
ACE inhibitors (e.g. ramipril) titrated as high as tolerated
Atenolol (or another beta blocker – usually bisoprolol) titrated as high as tolerated
Aldosterone antagonist for those with clinical heart failure (i.e. eplerenone titrated to 50mg once daily)
If a patient has acute coronary syndrome and they develop chronic heart failure, which of the following medications should they be started on?
1 - Spirolactone
2 - Doxazosin
3 - Furosemide
4 - Bendroflumethiazide
1 - Spirolactone
Eplerenone is a suitable alternative
Which of the following carries the biggest risk in patients taking a combination of spironolactone/eplerenone plus an ACE inhibitor or angiotensin receptor blocker?
1 - hypocalcaemia
2 - hypophosphataemia
3 - hypokalaemia
4 - hyperkalaemia
4 - hyperkalaemia
Can be fatal
Treat with calcium gluconate and or K+ binders or 5-10 units of insulin
Which of the following is NOT a complication of acute coronary syndrome?
1 - Death
2 - Rupture of the heart septum or papillary muscles
3 - oEdema” (heart failure)
4 - Arrhythmia and Aneurysm
5 - Liver cirrhosis
6 - Dressler’s Syndrome
5 - Liver cirrhosis
Dressler’s syndrome occurs around 2 – 3 weeks post acute MI - localised immune response
- inflammation of the pericardium, the membrane that surrounds the heart (pericarditis)
- presents with pleuritic chest pain, low-grade fever and a pericardial rub on auscultation
- global ST elevation and T wave inversion
- echocardiogram (pericardial effusion) and raised inflammatory markers (CRP and ESR).
- manage with NSAIDs (e.g., aspirin or ibuprofen) and, in more severe cases, steroids (e.g., prednisolone)
- Pericardiocentesis may be required to remove fluid from around the heart, if there is a significant pericardial effusion.
Types of MI:
Type 1: Traditional MI due to an acute coronary event
Type 2: Ischaemia secondary to increased demand or reduced supply of oxygen (e.g. secondary to severe anaemia, tachycardia or hypotension)
Type 3: Sudden cardiac death or cardiac arrest suggestive of an ischaemic event
Type 4: MI associated with procedures such as PCI, coronary stenting and CABG
You could remember these with the “ACDC” mnemonic:
Type 1: A – ACS-type MI
Type 2: C – Can’t cope MI
Type 3: D – Dead by MI
Type 4: C – Caused by us MI
In LBBB we can write William across the ECG leads as per the image
OR
Turn ECG clockwise and look at lead V1, if it points to the left, this is a LBBB
LBBB can be seen in MI
In RBBB we can write Marrow across the ECG leads as per the image
OR
Turn ECG clockwise and look at lead V1, if it points to the right, this is a RBBB
