Acute Coronary Syndromes

Question 1

Briefly outline the pathophysiology of atherosclerosis.

Answer 1

1. Endothelial damage allows LDL infiltration, which oxidise and form foam cells that accumulate = fatty streak.
2. Thrombogenic fatty streak promotes SMC proliferation and forms a fibrous cap = plaque.
3. Calcium crystals deposited by SM form under plaque = stiffening.
4. Brittle fibrous cap prone to rupture, causes clot in stiff vessel.

Question 2

When do the coronary arteries perfuse?

Answer 2

L) ventricle perfuses during diastole
R) ventricle perfuses during both (mostly systole)

Question 3

The RCA supplies…? (5)

Answer 3

1. Right atrium
2. Right ventricle
3. SA node via SA nodal artery
4. AV node via septal perforators
5. Posterior septum via PDA (60% of pop, right-dominance)

Question 4

The LMCA supplies…? (5)

Answer 4

1. Left atrium via LCx
2. Anterior left ventricle via LAD
3. Posterolateral wall of left ventricle via LCx
4. Anterior portion of septum via LAD
5. Posterior septum via PDA (20% of pop, left-dominance)

Question 5

List the full STEMI criteria (5)

Answer 5

Persistent Sx with ECG features in 2 contiguous leads:
1. Men under 40 - ≥2.5 mm STE in V2-V3
2. Men over 40 - ≥2 mm STE in V2-V3
3. All women - ≥1.5 mm STE in V2-V3
4. ≥1 mm STE in all other leads
5. New LBBB

Question 6

List the Modified Sgarbossa criteria.

Answer 6

Paced rhythm or LBBB with:

1. Concordant STE ≥1mm in ≥1 lead
2. Concordant STD ≥1mm in ≥1 lead
3. Proportionally excessive discordant STE in ≥1 lead anywhere with ≥1mm STE as defined by ≥25% depth of the preceding S wave

Question 7

What is a STEMI equivalent that is highly suspicious for inferior MI?

Answer 7

Elevation of any degree in two contiguous inferior leads with any amount of depression in aVL is highly suspicious for inferior OMI

Question 8

New _______ with new ________ is highly suspicious for proximal LAD occlusion. Why?

Answer 8

New RBBB with new LAFB (bifascicular block).
Proximal LAD septal perforators perfuse the RBB and anterior fascicle of the LBB, while the RCA perfuses the posterior fascicle.

Question 9

What are the three elements that make a T wave hyperacute?

Answer 9

1. TW is disproportionately large in relation to R wave
2. Wider than normal TW
3. More symmetrical than normal TW