Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

1Principles of Biomedicine - MD1 > 59 - Ischaemic Heart Disease > Flashcards

59 - Ischaemic Heart Disease Flashcards

1
Q

Ways that the heart can increase coronary artery blood supply
1)
2)

A

1) Dilate coronary arteries

2) Reduce heart rate (blood fills coronary arteries only during diastole)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Angina pectus

A

Insufficient O2 to meet cardiac muscle needs

Reduced perfusion rather than inadequate blood [O2]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Stable angina

A

Chest pain with exertion, stress

Associated with coronary artery disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Variant angina

A

Coronary vasospasm at rest.

Unknown mediator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Unstable angina

A

Angina at rest and with effort

Potential for thrombus formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Aims of stable angina treatment
1)
2)
3)

A

1) Prevent attacks
2) Relieve symptoms
3) Prevent progression to heart attacks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does drug treatment for stable angina aim to do?

A

Increase O2 supply to heart, reduce heart O2 consumption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why might dilation of coronary arteries be difficult in stable angina?

A

Atheromatous arteries difficult to dilate.

Arteries might already be maximally-dilataed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Ways to decrease heart O2 demand
1)
2)
3)

A

1) Decrease cardiac output (stroke volume, heart rate)
2) Reduce preload (dilate veins, reduce venous return)
3) Reduce afterload (dilate arterioles, decrease resistance)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Drugs with which preload can be decreased in stable angina

A

Nitrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Drugs with which afterload can be decreased in stable angina

A

Ca2+ channel blockers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Drugs with which cardiac output can be decreased in stable angina
1)
2)
3)

A

1) Ca2+ channel blockers
2) Beta-adrenoceptor antagonists
3) Ivabradine
All these affect myocardium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q 
Nitrates mechanism of action 
1)
2)
3)
4)
5)
A

1) Drug undergoes biotransformation, releases NO
2) NO stimulates guanylate cyclase in cell
3) Guanylate cyclase increase cGMP levels in cell
4) cGMP inhibits Ca2+ entry into cell, preventing Ca2+ activating myosin light chain kianse, which activates myosin light chain.
5) Relaxation of vascular smooth muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Effects of nitrates on angina
1)
2)
3)

A

1) Relaxation of veins leads to decreased preload
2) Relaxation of large arteries leads to decreased afterload
3) Relaxation of coronary arteries leads to no increase in flow with fixed stenosis, and no diversion of blood from ischaemic area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Short-acting nitrate

A

Glyceryl trinitrate (GTN)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why must glyceryl trinitrate be given IV, transdermally or sublingually?

A

Subject to extensive first-pass metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What can glyceryl nitrate not be stored in?

A

Plastic, as adsorbs to plastic, is unstable.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

When is glyceryl trinitrate given sublingually?

A

For acute attack, if anticipating effort

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Longer-acting nitrate

A

Isosorbide dinitrate

20
Q

Isosorbide dinitrate administration

A

Administrated orally.

First-pass metabolism converts into active metabolite (isosorbide-5-mononitrate)

21
Q 
Adverse effects of nitrates
1)
2)
3)
4)
A

1) Affects other smooth muscle (relaxation of airways, gut). Not clinically significant.
2) Postural hypotension (venous pooling)
3) Headache, flushing (arterial dilation)
4) Reflex tachycardia

22
Q

How is reflex tachycardia from nitrate use dealt with?

A

Often used in combination with beta-adrR or cardiac-selective Ca2+ blockers to minimise reflex tachycardia

23
Q

Drug contraindicated with nitrates

A

Sildenafil (viagra).

Viagra is a phosphodiesterase inhibitor, reduces cGMP breakdown.

24
Q 
Tolerance to nitrates
1)
2)
3)
4)
A

1) Depletion of tissue thiols required for NO production from glyceryl trinitrate
2) Increased release of, sensitivity to vasoconstrictors (EG: angiotensin II)
3) Increased endothelial free radical scavenging NO, reducing bioavailability of NO
4) Reduced or abnormal activity of muscle mitochondrial ALDH2, decreased NO activity

25
Q

What is required to minimise nitrate tolerance

A

Drug-free period.

Remove patch overnight

26
Q

Example of a cardiac-specific Ca2+ channel blocker

A

Nifedipine (14-times more cardioselective than vasoselective)

27
Q

Effect of Ca2+ blockers on angina

A

Decreased HR, SV, CO, reduced demand.

Arterial dilation, reduced afterload.

28
Q

Ca2+ blockers mostly prescribed for angina

A

Verapamil, diltiazem

29
Q

How are Ca2+ blockers used to treat angina?

A

Prophylactically

30
Q

Drug that is never taken with a beta blocker

A

Verapamil

31
Q

Effect of beta blockers on angina
1)
2)

A

1) Decreases contractility, stroke volume - Decreased cardiac output and demand
2) Decreases heart rate (affects SA, AV nodes) - Increased diastole time, increased coronary perfusion

32
Q

First-line prophylactic therapy for angina

A

Beta-blockers (atenolol is cardiac-selective)

33
Q

Are nitrates, Ca2+ blockers and beta-blockers disease-modifying?

A

No.

34
Q

Novel angina therapy

A

Ivabradine

35
Q

Ivabradine effect

A

Decreases heart rate.

Reduces myocardial oxygen demands, increases diastole time.

36
Q

Ivabradine mechanism

A

Selectively inhibits Na+/K+ If current in SA node.

This decreases the frequency of atrial depolarisation

37
Q

Below what heart rate does Ivabradine cease to have an effect?

A

70bpm

38
Q

Is Ivabradine disease-modifying?

A

Yes. Decreases risk of myocardial infarct

39
Q

Adverse effects of Ivabradine
1)
2)

A

1) Brightness in visual field

2) Conduction abnormalities

40
Q

Precautions to take with Ivabradine

A

Antibiotics, antifungals can increase Ivabradine levels

41
Q

Angina drugs that decrease heart rate
1)
2)
3)

A

1) Ivabradine
2) Beta-blockers
3) Ca2+ channel blockers

42
Q

Angina drugs that decrease stroke volume
1)
2)

A

1) Beta-blockers

2)

43
Q

Angina drugs that decrease afterload
1)
2)

A

1) Ca2+ channel blockers

2) Nitrates (not so much)

44
Q

Angina drug that decreases preload

A

Nitrates

45
Q

How is variant angina treated?
1)
2)
3)

A

1) Short acting nitrate relieves coronary spasm
2) Dihydropyridine (Ca2+ channel blocker) prophylaxis
3) Don’t use beta-AdrR antagonists (contraindicated)

46
Q

Treatment for unstable angina

A

Same as for stable angina, but include aspirin to prevent thrombosis

47
Q

Why can some antibiotics and antifungals increase Ivabradine half-life?

A

Ivabradine metabolised in liver through cytochrome P450.

If antibiotics or antifungals are also metabolised in this wal, can slow metabolism.

1Principles of Biomedicine - MD1 (157 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions