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Year 1-Cardiovascular System > Arrhythmia Therapies > Flashcards

Arrhythmia Therapies Flashcards

1
Q

What is an arrhyhmia?

A

A deviation from the normal heart rhythm

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2
Q

What is sinus arrhythmia?

A

Irregular heart rhythm. Normal in most cases

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3
Q

What are the two main groups of tachyarrhythmias?

A

Supraventricular arrhythmia
Ventricular arrhythmia

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4
Q

What is the difference between ventricular defibrillation and ventricular tachycardia?

A

VT- rapid, regular tachycardia
VF- rapid, irregular tachycardia

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5
Q

RECAP- what is the conc. of the inside of a cell compared to the outside?

A

Negative

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6
Q

Discuss what happens to charge when an action potential occurs.

A

Starts off negative, is positive during depolarisation and goes negative upon repolarisation

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7
Q

In terms of the Vaughan-William’s classification, what channels do class one antiarrhythmics act on?

A

Sodium channels

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8
Q

In terms of the Vaughan-William’s classification, what channels do class two antiarrhythmics act on?

A

Beta adrenergic receptors.

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9
Q

In terms of the Vaughan-William’s classification, what channels do class three antiarrhythmics act on?

A

Potassium channels

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10
Q

In terms of the Vaughan-William’s classification, what channels do class four antiarrhythmics act on?

A

Calcium channels

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11
Q

In terms of the Vaughan-William’s classification, what channels do class five antiarrhythmics act on?

A

Any other than classes 1-4

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12
Q

What do sodium channel blocker drugs do (class 1)?

A

Membrane-stabilizing agents so-
-Decrease the amplitude (size of Action potential)
-Reduce velocity of conduction/Excitability

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13
Q

Class one sodium channel blocker drugs are divided into which three subdivions?

A

A, B, C

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14
Q

Give an example of a Class 1A sodium channel blocker.

A

Quinidine

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15
Q

Give an example of a Class 1B sodium channel blocker.

A

Lidocaine

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16
Q

Give an example of a Class 1C sodium channel blocker.

This is the most clinically used one so good to remember it :)

A

Flecainide

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17
Q

Describe the effect flecainide has on the action potential.

A

Slows down depolarisation and shortens the plateau phase

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18
Q

Give three examples of common beta-blockers (class 2).

A

Atenolol, bisoprolol, propranolol

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19
Q

What do beta blockers do?

A

Acts via β1 receptors to block sympathetic stimulation of the heart

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20
Q

Describe the effect of beta blockers on the action potential.

A

Prolongs phase 4 depolarization
Shortens plateau phase

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21
Q

What is the first line choice of medication for atrial fibrillation?

A

Beta blockers, usually bisoprolol

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22
Q

Give some examples of potassium blockers (class 3).

A

Amiodarone, bretylium, sotalol

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23
Q

Describe the effect of potassium channel blockers on the action potential.

A

Increases the duration of the action potential by prolonging repolarisation in phase three and the effective refectory period.

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24
Q

Which potassium channel blocker is most commonly used?

A

Amiodarone

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25
Give two examples of calcium channel blockers.
Verapamil, diltiazem
26
Describe the effect of calcium channel blockers on the action potential.
Depress phase 4 depolarization in SA and AV nodes, slowing the heart rate Shorten phase 2 Plateau phase (reduce contractility)
27
What are two important drugs in Class 5?
Digoxin, adenosine
28
What does digoxin do?
Inhibits the sodium-potassium ATPase pump
29
Describe the effect of digoxin on the action potential.
Reduces the refractory period in myocardium
30
When might you use digoxin?
In patients with particularly troublesome to control atrial defibrillation or atrial flutter Second line treatment so might be prescribed alongside something else
31
On an ECG, what would be a sign of digoxin toxicity?
‘Reverse tick’ appearance of ST segment in lateral leads
32
What is one of the issues when trying to treat digoxin toxicity?
It has a long half life
33
When is digoxin toxicity more severe?
When potassium levels are low
34
What does adenosine do?
Blocks conduction of the AV node
35
What is adenosine used for?
Used to convert paroxysmal supraventricular tachycardia to sinus rhythm
36
What is the half life like for adenosine?
Very short
37
What can antiarrhythmic drugs end up causing?
Arrhythmia
38
What is the most common type of arrhythmia?
Atrial fibrillation
39
What score can identify a patient's risk of a stroke?
CHADS-VASC score
40
What is important to note about the CHADS-VASC score?
If you are over 75, you get two points, <75=1 point
41
Who is more at risk of having a stroke due to atrial fibrillation- men or women?
Women
42
What is the CHADS-VASC score?
A scoring method used to see how likely someone is to have a stroke due to atrial fibrillation.
43
A CHADS-VASC score or 2 or greater suggests what?
Moderate/high risk of stroke
44
A CHADS-VASC score of one suggest?
Low/moderate risk of stroke
45
What are some of the risks of using the drugs warfarin and clopidogrel?
Can cause bleeding, like anticoagulants
46
What are the three main groups of anticoagulants?
Vitamin K antagonist Direct Thrombin Inhibitor Direct Xa (10a) inhibitors
47
Give an example of a vitamin K anticoagulant.
Warfarin
48
Give an example of a direct thrombin inhibitor.
Dabigatran
49
List some direct xa (10a)inhibitors.
Rivaroxaban, Apixaban, Edoxaban
50
What do direct thrombin inhibitors, like dabigatran, do?
Prevents activation of fibrinogen into fibrin.
51
What do direct xa inhibitors do?
They inhibit factor 10a production, preventing prothrombin being converted into thrombin.
52
How does warfarin work?
Inhibits Vitamin K epoxide reductase Reduced levels of vitamin K
53
What happens when there are reduced levels of vitamin K?
Cannot produce clotting factors
54
How can you monitor warfarin therapy?
By measuring the INR (international normal ratio)
55
How is INR calculated?
Actual PROTHROMBIN time -------------------------------------------- Standard PROTHROMBIN time
56
What are the main adverse effects of warfarin?
-Can cause bleeding -Can interact with many other drugs -Has to be avoided in some phases in pregnancy
57
Which score calculates a patient's risk of bleeding while on warfarin?
HAS-BLED score
58
How does aspirin and Sulfonamides increase the activity of warfarin?
Decreased binding to albumin, leading to an increase in INR
59
How can antibiotics increase the activity of warfarin?
Antibiotics interfere with the absorption of vitamin K so reduced clotting factors
60
Which drugs can interact with warfarin and increase risks of bleeding?
Anticoagulants like aspirin Heparin antimetabolites
61
How can aspirin interact with warfarin to increase bleeding risks?
They affect platelet function
62
How can vitamin K decrease warfarin activity?
Promotes clotting factor synthesis
63
List some of the inhibitors of cytochrome P450
I am not expected you to remember these all, lecturer just said it was a good idea to have a basic idea of inhibitors/ inducers :) Omeprazole Disulfiram Erythromycin Valproate Isoniazid Ciprofloxacin and Cimetidine Ethanol (acutely) Sulphonamides
64
List some of the inducers of cytochrome p450
I am not expected you to remember these all, lecturer just said it was a good idea to have a basic idea of inhibitors/ inducers :) Alcohol (chronic use) Barbiturates Carbamazepine Phenytoin Rifampicin Sulphonylureas
65
How can cytochrome p450 have an effect on the activity of warfarin?
Warfarin is metabolised by cytochrome p450 enzymes

Year 1-Cardiovascular System (41 decks)

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