SBM: Pharmacology & therapeutics - Cardiology Flashcards

1
Q

name 4f factors controlling coronary circulation

A

Arterial pressure Cardiac cycle Heart Rate Direct sensitivity of arterioles to anaerobic metabolites`

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2
Q

Compare coronary flow of a normal patient to one with coronary artery disease

A

Normal Pt: Flow can increase 8 fold in response to demand Disease: increase in flow is LIMITED

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3
Q

Angina What are the two types of angina

A

Stable + Unstable

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4
Q

Describe a patient with UNSTABLE angina

A

Unexpected usually occurs @ rest discomfort may be more severe and prolonged that typical angina

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5
Q

Describe a patient with STABLE angina

A

Episodes of chest discomfort Predictable - e.g. on exertion/stress

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6
Q

What is angina?

A

symptom of Myocardial Ischaemia myocardium does not get enough oxygen –> heart poorly supplied its blood wrt metabolic needs

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7
Q

list 6 (SIX) Anti-anginals

A

Nitrates Beta Blockers CCB Potassium channel activators metabolic manipulators Opiates

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8
Q

Name two types of nitrates used?

A

Nitroglycerin + Isosorbide dinitrate

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9
Q

What is Nitroglycerin used for?

A

Stable Angina

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10
Q

Explain the mechanism of nitroglycerin

A

Acts of vascular smooth muscle –> vasodilation Primarily works on veins (modest dilation of arterioles) Decrease myocardial oxygen demand

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11
Q

How does nitroglycerin decrease myocardial oxygen demand? (Ppt Notes)

A

it was first thought that GTN worked by dilating coronary vessels. However due to atherosclerosis - they believe it limits the dilation. therefore GTN works by dilating in the periphery. the reduction in PRELOAD and then the AFTERLOAD subsequently decreases the workload of the heart –> decreasing oxygen demand

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12
Q

Side effects of nitroglycerin

A

headaches, tachycardia, hypotension

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13
Q

Why would you use isosorbide dinitrate instead?

A

more stable that nitroglycerol longer lasting effect

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14
Q

What problem can arise with Isosorbide dinitrate?

A

Tolerance can occur - therefore give lowest dose

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15
Q

Beta blockers are used for what diseases? (How do you know they are B-blockers)

A

Hypertension, IHD, arrhythmias, hyperthyroidism, gluacoma (- olol)

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16
Q

How do B-Blockers work?

A

Competitive Beta receptor blockade - reduction in heart rate - increases diastolic filling time therefore reduces force of contraction

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17
Q

Put these in order of selective to non selective starting with NON SELECTIVE to selective metoprolol - atenolol - nebivolol - propranolol - bisoprolol - esmolol

A

propranolol - atenolol - metoprolol - bisoprolol - nebivolol - - esmolol

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18
Q

What are the common side effects of B blockers

A

Bronchospam, hypotension, severe bradycardia,. cardiac failure

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19
Q

How do dihydropyridine CCB work?

A

Vasodilation NO CARDIAC SLOWING

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20
Q

What can dihydropyridine CCB be used for

A

IHD Hypertension

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21
Q

name 3 dihydropyridine CCB (how do you know a drug is a CCB)

A

Nefedipine, amlodipine, delodipine (- dipines)

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22
Q

What are rate slowing CCB

A

Vasodilator Cardiac slower

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23
Q

Name 2 Rate Slowing CCB

A

Verapamil Diltiazem

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24
Q

What are rate slowing CCB used for

A

IHD Hypertension Atrial arrhythmias

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25
Q

Name a potassium channel activator

A

Nicorandil

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26
Q

Action of Nicorandil?

A

Similar to nitrates Acts of vascular smooth muscle –> vasodilation Primarily works on veins (modest dilation of arterioles) Decrease myocardial oxygen demand

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27
Q

name 3 metabolic manipulators

A

perhexiline trimetazadine ranolazine

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28
Q

Describe the cardiac electrical activity

A

1) Beat initiated by spontaneous depolarisation of pacemaker cells in SAN 2) these cells trigger neighbouring cells to depolarise by DIRECT electrical contacts. A wave of depolarisation spreads across atria - contracts. 3) The signal eventaully excites the AVN 4) AVN to ventricle by Bundle of His (conducting tissues - derived from modified cardiac muscle - Purkinje fibers) 5)

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29
Q

What is the Bundle His made from?

A

derived from modified cardiac muscle - Purkinje fibers

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30
Q

When do arrhythmias occur? (3)

A

1) when the hearts NATURAL pacemaker develops an abnormal rate/rhythm 2) when normal conduction path is interrupted 3) ???? When another part of the heart takes over as pacemaker (UNDERSTAND?)

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31
Q

What does Tachycardia mean?

A

fast

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32
Q

What does Bradycardia mean?

A

slow

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33
Q

what qualifies as a tachyarrhythmias?

A

>100bpm

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34
Q

What tachyarrhythmias is Supraventricular?

A

AF Atrial flutter ‘SVT’

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35
Q

What does SVT mean?

A

Supraventricular ttachyarrhythmias - that is NOT AF/Atrial flutter

36
Q

What tachyarrhythmias are Ventricular

A

VT VF Torsade de Pointes

37
Q

What does VT mean?

A

Means there is an arrhythmia in theventricle, which started by an ectopic and then developing a short circuit of depolarisation and depolarisation within the ventricle.

38
Q

What is shown in this ECG?

A

VT

39
Q

What is shown in this ECG?

A

VF

40
Q

What is the aim of antiarrhythmic drugs?

A

Reduce ectopic pacemaker activty + modify critically impaired conduction.

41
Q

what makes an ideal anti-arrhythmic drug?

A

Work on ectopic pacemaker and depolarised tissue more than on normal depolarising tissues

42
Q

How do anti-arrhytmic drugs work?

A

Altering ion flxues (Na,Ca,K) within excitable tissues in the myocardium.

43
Q

what is used to classify anti-arrythmic drugs?

A

Singh-Vaugn Williams system

44
Q

What are the 4 classes of anti arrythmic drugs?

A

Class 1: Na channel blockers

Class 2: B blockers

Class 3: K Channel Blockers

Class 4; Ca Channel Blockers

45
Q

Where do each of the classes work?

A
46
Q

How do Class One anti-arrythmic drugs work?

A

block the Fast inward sodium channel

47
Q

How are class 1 anti arrythmic drugs subdivided? based on what?

A

IA, IB, IC

Based on potency towards blocking teh sodium channel

and effects on repolarisation

48
Q

What does IA classify for?

Examples?

A

High/Intermediate potency

Prolong Repolarisation - prolong QT interval

Quinidine, disopyramide

49
Q

What does IB classify for?

Example?

A

Lowest potency

shorten repolarisation

Decrease QT interval

E,g Lidocaine, Mexiletine

50
Q

What does IC classify for?

Example?

A

Most potent sodium channel blocking agents

Prolong QRS interval

Little effect on repolarisation - NO EFFECT ON QT interval

E.g. Flecainide, propafenone.

51
Q

What is Disopyramide? What is it used for?

A

Disomyrapide is a sodium channel blocker

Used for Supraventricular arrythmias

And in ventricular arrythmias BUT only in pt with good ventricular fucntion because of its negative inotrophic effects.

Has anti-cholinergic effects.

52
Q

trick…

What is dipyridamole?

A

Antiplatelet used in stroke

53
Q

What is Lidocaine / Mexiletine

A

Sodium Channel blockers

Lidocaine - It is used IV only - because of its first pass metabolism

mexiletine is orally active

54
Q

Propafenone is what class of anti-arrythimic drug?

A

Class IC

used to treat supraventricular arrythmias

used to suppress life threatening ventricular arrhythmias

Structurally similar to propranolol and has beta blocking activity aswell.

THEREFORE CONSIDER WHEN GIVING IN HEART FAILURE PATIENTS

55
Q

How do Class 2 Anti arrhythmias work?

What are class 2?

A

acts indircetly by blocking beta-adrenergic receptors.

Slow sinus rhythm,

prolong PR interval

Beta Blockers - olols

56
Q

What are class 3 anti arrhythmic drugs?

Examples?

A

K channel blockers

prolongs reploarization

Prolong QT interval

No effect on QRS interval

Little effect on rate of depolarisation

Block fast outward K+ - Amiodarone, Sotalol

Block slow INward Na+ current: Ibutilide

57
Q

What are class 4 anti-arrhythmic drugs?

Example

A

CCB

relatively selective AV nodal CCB

Slow sinus rhythm

Prolong QR interval

Verapamil, diltiazem

58
Q

How do class 3 anti arrhythmic drugs work?

A

K Channel blockers

prolong repolarisation by blocking outward K.

59
Q

What do you treat intractable ventricular arrhythmias with?

A

Amiodarone

Sotalol

60
Q

Amiodarone is used to treat what? Whats its mechanism of action?

A

treat intractable ventricular arrhythmias.

mechanism: block fast outward K current.

61
Q

What does amiodarone do to the QT interval?

A

Prolong it

62
Q

What is used to treat ventricular arrhythmias?

A

IV Amiodarone

Which is superior to IV lidocaine.

63
Q

What is Mexiletine used for?

A

it is the orally active form of lidocaine.

It is a class 1 B anti arrythmic drug

64
Q

With the best of your ability, describe the Dynamics of amiodarone.

(Half life?)

A

It can take several weeks to months for amiodarone to achieve stready state plasma levels.

Takes months to clear with an elimination half life from 26-107

65
Q

Side effects of amiodarone?

A

Pulmonary fibrosis

Hepatotoxcity

Hyper/Hypothryoidism (amiodarone is structually similar to thyroid hormone + has lots of iodine)

peripheral neuropathy

Skin reactions,

66
Q

What is class 4 anti arrhythmic drugs?

Example?

A

CCB

Prolong repolarisation by blocking inward calcium (therefore keeping cell more +ve than it should be)

prolong QT

Example: verapamil, ditiazem

67
Q

Talk about Verapamil.

A

useful in supraventricular arrhythmias

more effective than digoxin for Ventricular rate control in AF

High doses can cause AV or SA block

68
Q

What is Adenosine

A

An anti arrythmic drug

For paroxysmal SVT

Used to terminate arrhythmias (blocks reentrant pathway).

69
Q

How should you give Adenosine

A

IV only

It has a short half life

70
Q

What is the half life of adenosine

A

extremely short half life

71
Q

What do you use Digoxin for?

A

AF

72
Q

What is epinephrine used for?

A

bradycardia

73
Q

why do you give adenosine?

A

Given as a rapid IV bolus to acutely treat paroxysmal SVT

74
Q

How does adenosine work?

A

potently block AV nodal conduction within 10-30 seconds of administration

75
Q

How long is the half life of adenosine?

A

extremely short

1.5-10seconds

76
Q

What is digoxin? and how does it work?

A

cardiac glycoside

acts by inhibiting the Na/K ATPase

Increase vagal tone, thus inhibiting AV nodal conduction.

77
Q

What is digoxin used for?

A

Control ventricular rate in patients with atrial tachycardias.

78
Q

what drugs would you give in VF

A

IV Lidocaine

IV Amiodarone

79
Q

What drugs would you give in VT

A

Amiodarone

Class 1, Class 3

80
Q

What drug would you give to Atrial arrythmias to control ventricular response?

A

Digoxin

IV Adenosine

Class 2

Class 4

81
Q

What does high doses of verapamil do?

A

Cause AV block or suppression of SA Node.

82
Q

To treat the atrial arrythmias what drugs would you give?

A

Class 3,

Class 1A,

Class1C

83
Q

to treat torsades de pointes:

acute:

Chronic:

A

to treat torsades de pointes:

acute: magnesium, isoproterenol

Chronic: Class 2

84
Q

What is torsade de pointes?

A

polymorphic arrhythmia which can rapidly develop into VF

85
Q

Recognise this ECG?

A

Torsade de pointes

86
Q
A