L8 - Angina

Question 1

What is ischaemia? What can it lead to?

Answer 1

• interruption of cardiac blood supply due to blocked in vessels, primarily involving coronary vessels
• lack of nutrients and oxygen leading to tissue death

Question 2

Why does ischaemia occur?

Answer 2

• as a consequence of atherosclerosis (coronary artery disease)
• plaque build-up in vessels causing blockage

Question 3

What is the spectrum of ischaemic heart disease?

Answer 3

early stages: angina

later stages: acute MI

Question 4

What is angina?

Answer 4

pain in chest caused by decreased blood supply to myocardium due to atherosclerosis
- it can be a symptom of coronary artery disease

Question 5

What is atherosclerosis?

Answer 5

hardening and narrowing of arteries due to plaque formation (deposition of fatty material in arteries)

Question 6

What are the 4 stages of cardiovascular disease?

Answer 6

• normal
• fatty streak
• fibrous plaque
• advanced plaque

Question 7

describe the 1st stage of CVD

Answer 7

NORMAL

• normal blood flow and BP
• exposed to risk factors
• initial lesion occurs = macrophage infiltration

Question 8

What are the risk factors of CVD?

Answer 8

• diet
• inflammation
• poor oral health
• hypertension
• diabetes
• smoking
• weight

Question 9

describe the 2nd stage of CVD

Answer 9

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

Question 10

describe the 3rd stage of CVD

Answer 10

FIBROUS PLAQUE

• hardening of the arteries (calcification of fatty streak)
• plaque continues to progress and expand

Question 11

describe the 4th stage of CVD

Answer 11

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

Question 12

What are the types of angina?

Answer 12

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

Question 13

What are the 3 things involved in the management of stable angina?

Answer 13

• dilation of coronary arteries (increase blood supply)
• control HR and force of contraction (reduce work load of heart)
• reduce CV risk factors

Question 14

What is the 1st line treatment for acute attacks?

Answer 14

GTN - dilation of coronary arteries

Question 15

What drug class is GTN and how does it work?

Answer 15

• nitrate
• mimics endogenous NO and causes non-specific vasodilation
• increases blood supply to the heart (coronary arteries) and reduces cardiac work (venous dilation)

Question 16

How is GTN administered?

Answer 16

• sublingual spray

- rapid onset + short lived

Question 17

How does NO cause vasodilation?

Answer 17

• acts on vascular smooth muscle to increase guanylate cyclase activity
• increased cGMP activates kinases
• promotes smooth muscle relaxation
• cGMP terminated by phosphodiesterase (PDE5)

Question 18

What are the side effects of GTN?

Answer 18

dose related side effects:

• hypotension
• headaches
• flushing
• reflex tachycardia

Question 19

When is GTN used?

Answer 19

first line treatment for acute angina attacks

Question 20

What are other treatments for angina? (chronic treatment)

Answer 20

beta blockers or calcium channels blockers- control HR and force of contraction

Question 21

What are beta blockers? What is a feature of them?

Answer 21

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

Question 22

selective/non-selective B blockers: where do they act?

Answer 22

non-selective: block B1 and B2 receptors

selective: B1 receptors

Question 23

What are three B blockers and how are they different?

Answer 23

propranolol: non-selective B blocker, cross BBB
metoprolol: B1 selective, cross BBB
atenolol: B1 selective, cannot cross BBB

Question 24

What are B blockers used for?

Answer 24

• primarily angina
• tachycardia
• hypertension
  not 1st line in combination with diuretic

Question 25

What are the adverse effects of B blockers?

Answer 25

B1 mediated:
- fatigue/ poor exercise tolerance
- CNS effects (if cross BBB)
B2 mediated:
- bronchoconstriction in lungs
- worsening lipid profiles
- hypoglycaemia
- increased toxicity in elderly

Question 26

How do CCBs work?

Answer 26

they inhibit Ca2+ influx through L-type calcium channels

Question 27

What effect do CCBs have on different parts of the heart?

Answer 27

• cardiac muscle: reduce force of contraction
• SA nodal tissue: reduce rate of contraction
• AV node: decrease conduction velocity

Question 28

What are the 2 types of CCBs? What makes them different?

Answer 28

• cardiac specific: require open channel in order to bind and block the pore = able to act in the heart because channels frequently open
• vessel specific: stabilises inactive channel = only able to act in vessels where channels less frequently open

Question 29

What are the cardiac and vessel selective CCBs?

Answer 29

verapamil and diltiazem

Question 30

What is the vessel specific CCB?

Answer 30

nifedipine

Question 31

What are the cardiac specific CCBs used for and why?

Answer 31

• mainly angina
  because increase oxygen supply and decrease oxygen demand
• hypertension
  causes vasodilation and reduces HR and force of contraction
• tachycardia
  reduces HR and slows contraction of the heart

Question 32

What are the adverse effects of cardiac specific CCBs?

Answer 32

• generally well tolerated
• most side effects vascular related e.g. flushing
• dose-related effects e.g. hypotension + bradycardia
  can cause cardiac depression if used with B blockers

Question 33

What is the vessel specific CCB used for?

Answer 33

• newer 1st line treatment for hypertension especially in elderly with vessel stiffness

Question 34

What are the side effects of vessel specific CCBs?

Answer 34

• don’t use alone in angina because causes reflex tachycardia and increased workload on heart
• most are dose dependent e.g. hypotension, flushing, dizziness + headache