MI Flashcards
What is an acute coronary syndrome? [1]
Give 3 examples [3]
Umbrella term for any condition where have reduced blood flow to heart muscle
E.g. STEMI, Non Stemi, Unstable angina
Label A-C, which highlights which arteries are affected by ECG changes
A = V1-V4: LAD
B: II, III & AVF: Right coronary artery
C: I, V5 & V6: circumflex
Which artery is occluded to cause this ECG?
a) LAD
b) RCA
c) LCA
d) circumflex artery
Which artery is occluded to cause this ECG?
a) LAD: Anterior ST elevation: V1-V4 elevated
b) RCA
c) LCA
d) circumflex artery
Which artery is occluded here? Explain what type of ACS is causing this ECG [1]
a) LAD
b) RCA
c) LCA
d) circumflex artery
Which artery is occluded here? Explain what type of ACS is causing this ECG [1]
a) LAD
b) RCA
c) LCA
d) circumflex artery: ST depression in V5 & V6
What is the difference in the pathology of STEMI vs non STEMI?
Pathophysiology of acute MI:
· NSTEMI
o Ruptured coronary plaque with sub-occlusive thrombus - impacted flow of oxygen to myocytes & therefore myocyte necrosis
o Plaques rupture when they are unstable and there is friction from passing blood (statins can stabilise the plaque)
o Thrombus forms but occludes part of the lumen
o NON-diagnostic ECG
· STEMI
o Ruptured coronary plaque with occlusive thrombus - impacted flow of oxygen to myocytes & therefore myocyte necrosis
o Thrombus forms occluding the whole lumen
o DIAGNOSTIC ECG
What is troponin? (for understanding)
Troponin: Ca2+ regulatory protein present in cardiac muscle. Forms complex with calcium ions and causes contraction of the muscle.
One end forms with Ca, the other forms with actin filaments.
Troponin is released into blood from the heart if there is stress from heart (e.g. plaque / blockages of arteries that supply the heart: starving o2 of oxygen). If damaged - troponin is released.
Acute MI: troponin is released !
Diagnosis of MI need which criteria? [3]
ALL OF:
- Acute MI - troponin must be elevated
- Rise and/or fall of troponin with at least one value >99th percentile of the Upper Range of Normality (URL)
3. Clinical evidence of acute MI
- Symptoms of acute MI
- ECG changes (Q wave)
- ID of coronary thrombus by angiography
- Imaging from MRI / Echo
How can you determine if a patient has ACS or instead has stable angina?
Stable angina:
- pain when doing exercise but goes away with resting (stenosis is stable, no rupture, no thrombus but narrowing is causing ischaemia)
ACS:
- Pain at rest > 15 mins
- Chest pain with nausea and vomiting, sweating and breathlessness, haemodyanomic instability
- Frequent pain despite no exertion
After patient examination, what would suggest an ACS? (risk factors)
Could be no signs
Risk factors:
- hypertension
- smoking / tabacco stains
- high lipids: Xanthelasma (harmless, yellow growth that appears on or by the corners of your eyelids next to your nose), Arcus lipidus (white, light grey, or blueish ring around the edge of the cornea)
Which artery is blocked here? [1]
Which area of the heart will this most likely be associated with? [1]
Which artery is blocked here? [1]
RCA - II, III and AVF STEMI.
Which area of the heart will this most likely be associated with? [1]
Inferior (most people are right dominated)
What is the treatment if a STEMI is detected? [3]
Open the occluded artery as soon as possible to restore blood flow to the heart (Time is Muscle) (angioplasty) at heart attack centre. less than120 mins is aim
If can’t open artery via stent aim to thromboylse (but want to avoid because have high risk of bleeding).
Reperfusion therapy:
- Aspirin + ticagrelor or pragural (dual antiplatelets)
- Heparin
- PCI
What is the treatment if a non- STEMI is detected? [5]
· Treatment:
o Aspirin + ticagrelor
o +/- GP IIb/IIIa inhibitor (prevent platelet aggregation by blocking glycoprotein IIb/IIIa receptors on their platelet’s)
o Fondaparinux - factor Xa inhibitor
o Anti-ischemic drugs - BB/nitrates
o Angiography, followed by +/- PCI within 24-96 hrs.
· Idea is to thin blood to fit through the semi-occluded gap - then use angiography within 24 hours of presentation to resolve the partial occlusion.
BATMAN
B – Beta-blockers unless contraindicated
A – Aspirin 300mg stat dose
T – Ticagrelor 180mg stat dose (clopidogrel 300mg is an alternative if higher bleeding risk)
M – Morphine titrated to control pain
A – Anticoagulant: Fondaparinux (unless high bleeding risk)
N – Nitrates (e.g. GTN) to relieve coronary artery spasm
Give oxygen only if their oxygen saturations are dropping (i.e. <95%).
What does this ECG indicate? [2]
STEMI in V1-V4
Q wave (has to be the first downward deflection AND is greater than 2mm in depth / width) indicates that MI infarct occured a while ago
What are the differences in troponin levels in STEMI vs non STEMI? [1]
NSTEMIs are defined as an injury to the cardiac muscle that results in an elevated troponin but lacks the ECG changes that define a STEMI.
What does this ECG indicate? [1]
How would you manage this patient? [3]
What does this ECG indicate? [1]
Non-stemi: ST depression
How would you manage this patient? [3]
Aspirin + antiplatelet (
What does this ECG indicate? [2]
T wave depression in V1-V3
Occlusion in LAD
How do you distinguish between NSTEMI and unstable angina? [1]
NSTEMI is differentiated from unstable angina by a dynamic elevation of troponin above the 99th percentile.
