Chest pain and Ischemic heart disease Flashcards
Explain the site, radiation and feeling of typical ischemic chest pain
Site: central, left-sided
Radiation: left/right/both arms, neck, jaw, back, epigastric, also pain may be isolated to these sites with no chest pain
Feeling: Heavy, ‘crushing’
Which area of the heart is most vulnerable to ischemia, why?
Sub endocardial area, as it’s closest to the LV cavity so myocardial wall pressure is greatest, blood vessels in this region are smaller and become extra vaso-constricted
How much must a lumen be occluded to experience angina?
How much is the lumen typically occluded to experience angina at rest?
about 70% normally, 90% occluded to experience angina at rest
Why is increased HR or occlusion detrimental to the perfusion of myocardium?
This shortens the time of diastole, and diastole is when heart muscle is relaxed, therefore coronary arteries are able to vasodilate and blood flow is at its max. A shortened diastole means there is less time for adequate blood to reach the myocardium
What are collateral vessels and where are they?
Why do they develop/expand?
Vessels that form perfusion links between smaller arteries and arterioles, but not between large arteries and the epicardium. They can develop/expand when the myocardium is ischemic and needs extra blood routes
What are the 2 components of a plaque
Fibrous cap and necrotic centre
Explain how the lumen of an artery would appear in someone with a stable angina
An intact plaque has formed above lipids, occluding the artery about 70%
What happens if a plaque inside a vessel breaks?
The fibrous cap undergoes erosion or fissuring, exposing the blood to thrombogenic substances in the necrotic centre
A platelet clot is formed and eventually a fibrin thrombus that occludes most of the lumen and can form a thromboemboli
Name 3 non-modifiable and 4 modifiable risk factors for ischemic heart disease
Also, name 6 lifestyle factors that can contribute to attaining IHD
Non-modifiable: age, male, family history
Modifiable: cigarette smoking, hypertension, diabetes, hyperlipidaemia
Lifestyle factors: stress, obesity, lack of exercise, unhealthy diet, depression, excessive alcohol
What is the key difference between a stable angina and an Acute coronary syndrome?
If the pain is reproducible in a stable angina: brought on typically by the same amount of exertion
Name the 3 types of Acute coronary syndromes and list them in order of increasing severity:
- Unstable Angina
- NSTEMI
- STEMI
What 2 things typically relieve stable angina pain, how long does it typically take?
Rest and/or nitrates in 5 minutes
What would you mainly use to diagnose a stable angina
The History
If you were to examine a patient with stable angina, name 4 things you might find
- Higher BP
- LV dysfunction
- Evidence of atheromas elsewhere, ie peripheral vascular disease
- corneal arcus
What is involved in an invasive CT coronary angiography?
A catheter is inserted into the radial or femoral artery and threaded to the aorta. A dye is then released that indicates the location of the blockage