What does ACS stand for?
Acute Coronary Syndrome
ACS is an umbrella term for unstable angina, NSTEMI, and STEMI.
What is the most common underlying cause of ACS?
Coronary Artery Disease (CAD)
CAD is a progressive condition characterized by fatty deposits (atheroma) in the coronary arteries.
7
What are the components of the pathophysiology of ACS?
- Build up of LDLs and inflammation in the tunica intima
- Atherosclerotic plaque formation
- Macrophages engulf LDLs -> Foam cell development
- Fibrous cap -> can rupture
- If ruptures -> lipids and collagen exposed to blood
- Platelet aggregation -> fibrin clot
- = partial/fully occluded artery
These factors lead to ischemia or infarction.
What does a STEMI indicate on an ECG?
ST elevation
STEMI is characterized by significant ST elevation in the ECG readings.
What does NSTEMI show on an ECG?
ST depression or T wave inversion
ST depression equal to or greater than 0.5mm at the J point in two or more contiguous leads indicates MI.
What ECG characteristics are indicative of a posterior and right sided MI
- ST depression in V1-3
- STE in inferior leads
What is Wellens Syndrome characterized by?
- Inverted T waves in V2-4
- Type A: biphasic
- Type B: deeply and symmetrically inverted
This pattern is seen in patients presenting with ischemic chest pain.
What is the mechanism of action (MOA) and dose of Aspirin?
- Blocks enzyme COX-1, preventing thromboxane A2 formation which reduces further thrombus formation
- 300mg
What do P2Y12 adenosine diphosphate antagonists do and name an example?
- Blocks P2Y12 ADP receptors on platelets
- Clopidogrel
What is the primary effect of GTN?
Potent vasodilator
GTN reduces myocardial workload and improves O2 delivery through preload and afterload modulation.
How does GTN modulate preload and afterload?
- Preload - dilation of venous vessels = decreased ventricular filling and lowers O2 demand
- Arterial dilation = reduced systemic vascular resistance
Dose and cautions of giving GTN
- 400-800mcg SL
- Bradycardic and hypotensive patients
- Inferior/Right sided MI
What is the MOA of Morphine in ACS management?
Binds to mu and kappa receptors, inhibiting pain transmission
Adequate pain relief is essential to reduce SNS response and cardiac workload.
What are the two types of antiemetics ?
- Ondansetron: 5HT3 antagonist
- Metoclopramide: dopamine D2 and 5HT3 antagonist
These medications help prevent nausea and enhance gastric emptying.
