L8 - Angina Flashcards
What is ischaemia? What can it lead to?
- interruption of cardiac blood supply due to blocked in vessels, primarily involving coronary vessels
- lack of nutrients and oxygen leading to tissue death
Why does ischaemia occur?
- as a consequence of atherosclerosis (coronary artery disease)
- plaque build-up in vessels causing blockage
What is the spectrum of ischaemic heart disease?
early stages: angina
later stages: acute MI
What is angina?
pain in chest caused by decreased blood supply to myocardium due to atherosclerosis
- it can be a symptom of coronary artery disease
What is atherosclerosis?
hardening and narrowing of arteries due to plaque formation (deposition of fatty material in arteries)
What are the 4 stages of cardiovascular disease?
- normal
- fatty streak
- fibrous plaque
- advanced plaque
describe the 1st stage of CVD
NORMAL
- normal blood flow and BP
- exposed to risk factors
- initial lesion occurs = macrophage infiltration
What are the risk factors of CVD?
- diet
- inflammation
- poor oral health
- hypertension
- diabetes
- smoking
- weight
describe the 2nd stage of CVD
FATTY STREAK
- accumulation of lipid-filled white blood cells including active WBC and “dead” cells containing cholesterol
- reduce elasticity of artery walls but doesn’t affect blood flow for decades
describe the 3rd stage of CVD
FIBROUS PLAQUE
- hardening of the arteries (calcification of fatty streak)
- plaque continues to progress and expand
describe the 4th stage of CVD
ADVANCED PLAQUE
- lumen so narrow blood can’t flow through anymore
- plaque becomes unstable and breaks off
- initiates clotting cascade
- can turn angina into MI
What are the types of angina?
Stable angina
- chest pain occurs when heart is working hard and needs more oxygen (stress and exercise)
- caused by narrow arteries
Unstable angina
- new chest pain or change in usual pattern of chest pain
- cause by clot formation
What are the 3 things involved in the management of stable angina?
- dilation of coronary arteries (increase blood supply)
- control HR and force of contraction (reduce work load of heart)
- reduce CV risk factors
What is the 1st line treatment for acute attacks?
GTN - dilation of coronary arteries
What drug class is GTN and how does it work?
- nitrate
- mimics endogenous NO and causes non-specific vasodilation
- increases blood supply to the heart (coronary arteries) and reduces cardiac work (venous dilation)
How is GTN administered?
- sublingual spray
- rapid onset + short lived
How does NO cause vasodilation?
- acts on vascular smooth muscle to increase guanylate cyclase activity
- increased cGMP activates kinases
- promotes smooth muscle relaxation
- cGMP terminated by phosphodiesterase (PDE5)
What are the side effects of GTN?
dose related side effects:
- hypotension
- headaches
- flushing
- reflex tachycardia
When is GTN used?
first line treatment for acute angina attacks
What are other treatments for angina? (chronic treatment)
beta blockers or calcium channels blockers- control HR and force of contraction
What are beta blockers? What is a feature of them?
B adrenergic receptor antagonists
- their degree of response is proportional to the level of sympathetic stimulation i.e. increased response in disease state, exercise, stress
selective/non-selective B blockers: where do they act?
non-selective: block B1 and B2 receptors
selective: B1 receptors
What are three B blockers and how are they different?
propranolol: non-selective B blocker, cross BBB
metoprolol: B1 selective, cross BBB
atenolol: B1 selective, cannot cross BBB
What are B blockers used for?
- primarily angina
- tachycardia
- hypertension
not 1st line in combination with diuretic
