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Flashcards in Arrhythmia - Therapy Deck (113):
1

What is arrhythmia?

A deviation from the 'normal' rhythm of the heart

2

What is a deviation from the normal rhythm of the heart called?

Arrhythmia

3

What are examples of arrhythmias?

Sinus arrhythmia

Tachycardias

Bradycardias (heart block)

4

What are examples of tachycardias?

Supraventricular arrhythmia (atrial fibrillation and supraventricular tachycardia)

Ventricular arrhythmia (ventricular tachycardia and ventricular fibrillation)

5

What does STC stand for?

Supraventricular tachycardia

6

What are examples of supraventricular arrhythmias?

Atrial fibrillation

Supraventricular tachycardia

7

What are examples of ventricular arrhythmias?

Ventricular tachycardia

Ventricular fibrillation

8

What are bradycardias also known as?

Heart block

9

What does the P wave of the ECG correspond to?

Activation of the atria

10

What does the QRS complex of the ECG correspond to?

Activation of the ventricles

11

What does the T wave of the ECG correspond to?

Recovery wave

12

What is the charge inside a cell relative to the outside?

Negative

13

What is the charge inside a cell at rest known as?

Resting membrane potential

14

Why is the resting membrane potential of a cell negative?

Uneven distribution of ions across the cell membrane

Dependent on the sodium-potassium ATPase pump (needs energy)

15

Talk about the concentration gradients of potassium, sodium and calcium inside and outside a myocyte?

Potassium greater concentration inside the cell

Calcium and sodium greater concentration outside the cell

16

What is used to classify antiarrhythmias?

Vaughan-Williams classification

17

What are the different classifications of antiarrhythmics?

IA

IB

IC

II

III

IV

V

18

What are class I antiarrhythmias?

Membrane stabilising agents

19

How do class I antiarrhythmias work?

Acts on fast sodium channel responsible for phase 0

Decreases the amplitude size (size of action potential)

Reduces velocity of conduction/excitability

20

What are the different categories of class I antiarrhythmias?

Ia

Ib

Ic

21

How do class IA, IB and IC vary in effect?

Different effect on action potential duration and therefore effective refractory period

22

What is an example of a class IA antiarrhythmias?

Quinidine

23

How does a class Ia antiarrhythmias work?

Moderate sodium channel blockade

24

How does a class I antiarrhythmias affect the effective refractory period?

Increases it

25

What is an example of a class IB antiarrhythmias?

Lidocaine

26

How do class IB antiarrhythmias work?

Weak sodium channel blockade

27

How do class IB antiarrhythmias affect the effective refractory period?

Decrease effective refractory period

28

What does ERP stand for?

Effect refractory period

29

What is an example of a class IC antiarrhythmias?

Flecainide

30

How do class IC antiarrhythmias work?

Strong sodium channel blockade

31

How do class IC antiarrhythmias affect the effective refractory period?

Do not change effective refractory period

32

What class I antiarrhythmias is the most common?

IC (flecainide)

33

When are class I antiarrhythmias most effective?

At high heart rates

34

If the graph represented class I antiarrhythmias, what would be IA, IB and IC?

1 - class IC

2 - class IB

3 - class IA

35

What are class II antiarrhythmias?

Beta blockers

36

What are examples of class II antiarrhythmias?

Atenolol

Bisoprolol

Propranolol

37

How do class II antiarrhythmias work?

Acts via B1 receptors to block sympathetic stimulation of the heart:

 

Prolongs phase 4 depolarisation

Shortens phase 2

38

How do class II antiarrhythmias prolong phase 4 depolarisation?

Slows SA discharge and AV conduction

Reduces excitability in non-nodial cardiac tissue

39

What does class II antiarrhythmias shortening phase 2 mean for contractility?

Negative effect on contractility

40

What are class II antiarrhythmias the first line for?

Atrial fibrillation (bisoprolol)

41

What is the first line for atrial fibrillation?

Class II antiarrhythmias (bisoprolol)

42

How do class III antiarrhythmias work?

Prolong refractiveness (slows K flow out of cells):

 

Increase action potential duration

Prolong repolarisation in phase 3

Prolongs effective refractory period

43

What are examples of class III antiarrhythmias?

Amiodarone

Bretylium

Sotalol

44

How do class III antiarrhythmias prolong refractiveness?

Slows K flow out of cells

45

What is amiodarone used for?

Ventricular tachycardia and occasionally in supraventricular tachycardia

46

What are problems with amiodarone?

Many interactions with other drugs (particular digoxin)

Striking side effects (thyroid, pulmonary fibrosis, slate, corneal deposits)

47

What is slate?

Grey pigmentation

48

What is grey pigmentation called?

Slate

49

How do class III antiarrhythmias increase the action potential duration?

Prolong repolarisation in phase 3

Prolongs effective refractory period

50

What effect do class III antiarrhythmias have on the effective refractory period?

Prolongs effective refractory period

51

What are class III antiarrhythmias used for?

Dysrhythmias that are difficult to treat

Life threatening ventricular tachycardia or fibrillation

Atrial fibrillation or flutter

52

What are class IV antiarrhythmias?

Calcium channel blockers

53

What are examples of class IV antiarrhythmias?

Verapamil

Diltiazem

54

How do class IV antiarrhythmias work?

Bind to Lcard type voltage gated calcium channels

Depress phase 4 depolarisation in SA and AV nodes (slowing heart rate)

Shortens phase 2 plateau phase

55

What effect does class IV antiarrhythmias shortening phase have on contractility?

Decrease contractility

56

When are class IV antiarrhythmias most effective?

At high heart rates

57

What are class IV antiarrhythmias used for?

Paraoxysmal supraventricular tachycardia

Rate control for atrial fibrillation and flutter

58

What are class V antiarrhythmias?

Others (do not fit into other categories, have properties of many different classes)

59

What are examples of class V antiarrhythmias?

Digoxin

Adenosine

60

What is digoxin?

Cardiac glycoside (increases output force of the heart and increases rate of contractions)

61

What effect does digoxin have on the heart?

Increases output force and increases rate of contractions

Increases vagal tone

Complex effect on cardiac action potential

Increases [Ca2+]

62

How does digoxin work?

Inhibits cellular sodium-potassium ATPase pump

 

63

What effect does digoxin increase vagal tone have?

Slows SA/AV node conduction

64

How does digoxin affect the cardiac action potential?

Reduces refractory period in myocardium

65

What is the half life of digoxin?

36-48 hours

66

What can be said about excretion of digoxin?

50-70% excreted almost entirely unchanged by kidneys

Excretion proportional to glomular filtration rate

67

What does GFR stand for?

Glomular filtration rate

68

What needs to be monitored when using digoxin?

Potassium levels

[digoxin]plasma

Toxicity

69

What is digoxin used for (indications for it)?

Atrial dysrhythmias (atrial fibrillation, atrial flutter, supraventricular tachycardia)

Heart failure

70

What does AF stand for?

Atrial fibrillation

71

What are examples of digoxin toxicity?

Nausea and vomiting

Xanthopsia

Bradycardia

Tachycardia

Arrhythmias (ventricular tachycardia and ventricular fibrillation)

72

What is xanthopsia?

Colour vision deficiency in which there is a prominance of yellow

73

What is a colour deficiency in which there is a predominance of yellow?

Xanthopsia

74

What are signs of dixogin toxicity?

Reverse tick appearance of ST segment in lateral leads

75

What is the treatment for digoxin toxicity?

Stop digoxin

If levels are very high adn risk of significant arrhythmias give digibind

76

What is digibind?

Digoxin immune antibody

Binds with digoxin forming complex molecules

Excreted in the urine

77

What makes digoxin toxicity more serious?

Low potassium levels

78

How does adenosine work?

Slows/blocks conduction through the AV node

79

What is adenosine used for?

Converting paroxysmal supraventricular tachycardia to sinus rhythm

80

What is the only way that adenosine can be administered?

As fast IV push

81

What is a possible side effect of adenosine?

May cause asystole for a few seconds

82

What is the half life of adenosine like?

Very short

83

What is sinus rhythm?

Any cardiac rhythm in which depolarisation of the cardiac muscle beings at the sinus node

84

What is any cardiac rhythm in which depolarisation of the cardiac muscle begins at the sinus node called?

Sinus rhythm

85

What side effect can all antiarrhythmias cause?

Arrhythmia

86

Other than antiarrhytmias, what else may be given?

Anticoagulants

87

What are indications for anticoagulation?

Atrial fibrillation

Metallic heart valves

Deep vein thrombosis

Pulmonary embolism

88

Why is atrial fibrillation an indication for anticoagulation?

Risk of stroke, peripheral emboli

89

What is the prophylaxis for deep vein thombosis/pulmonary embolism?

Surgery

High risk medical patients

Immobilisation

90

What are the 3 factors that contribute to thrombosis known as?

Virchow's triad

91

What are the 3 factors of Virchow's triad?

Stasis

Abnormal blood

Abnormal flow

92

What properties makes the idea anticoagulant?

Oral

No need for monitoring

No interaction with food or drugs

Given once or twice a day with fixed dose irrespective of weight or age

93

What are examples of anticoagulants?

Warfarin

Dabigatran

Rivaroxaban

Apixaban

Edoxaban

94

What is warfarin?

Vitamin K antagonist

95

How does dabigatran work?

Direct thrombin inhibitor

96

How does rivaroxaban, apixaban and edoxaban work?

Direct Xa inhibitors

97

How does warfarin inhibiting vitamin K allow it to be an anticoagulant?

Vitamine K is reduced to 'complete' clotting factors, warfarin prevents this

98

How is warfarin therapy monitored?

Regular international normalised ratio (INR)

Watch if therapy altered

Patient education

Alcohol intake

99

What does INR stand for?

International normalised ratio

100

What is international normalised ratio (INR)?

Actual prothrombin time/standard prothrombin time

101

What is the normal international normalised ratio (INR)?

1

102

What is the range of therapeutical international normalised ratio (INR)?

2.5-4 depending on the clinical indication

103

What are some adverse affects of warfarin?

Bleeding (dose related)

Interactions with multiple other drugs

Teratogenic

104

How is warfarin teratogenic?

Causes retroplacental and foetal intracerebral bleeding

Avoid in first and third trimester

105

What are some drugs that interact with warfarin and promote its activity?

Aspirin

Antibiotics (oral)

106

What are some drugs that interact with warfarin and decrease its activity?

Vitamine K

Barbiturates

107

What is cytochrome P450?

Proteins from the superfamily containing heme as a cofactor, involved in the formation and breakdown of various molecules

108

What are some inhibitors of cytochrome P450?

Omeprazole

Erythromycin

Ethanol

109

What are some inhibitors of cytochrome P450?

Alcohol

Barbiturates

110

What is a safe alternative to warfarin?

Direct oral anticoagulants (DOAC)

111

What does DOAC stand for?

Direct oral anticoagulants

112

How does atrial fibrillation prevalence change with age?

Massively increase, going for <1% of <65 years old to 10% in >75 years old

113

How does risk of stroke with atrial fibrillation change with age?

Increases with age

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