Arrhythmias treatment Flashcards

1
Q

What is Vaughan-Williams classification of drugs used to treat arrhythmias

A
Class 1
-Class Ia
-Class Ib
-Class Ic
Class II
Class III
Class IV
Other
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the electrophysiologic property of class IA

A

Fast* sodium-channel blockade

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

What is the electrophysiologic property of class IB

A

Intermediate* sodium-channel blockade

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

What is the electrophysiologic property of class IC

A

Slow* sodium-channel blockade

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

What is the electrophysiologic property of class II

A

Β-Adrenergic receptor antagonism

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

What is the electrophysiologic property of class III

A

Prolong refractoriness

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

What is the electrophysiologic property of class IV

A

Calcium channel blockade

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

What are class I drugs, and what do they all do

A

Membrane-stabilizing agents

- sodium channel blockers

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

What is examples of class Ia

A

quinidine, procainamide, disopyramide

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

How do class Ia drugs block sodium channels

A

Delay repolarization

Increase the action potential duration

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

What are class Ia drugs used for

A

Used for atrial fibrillation, premature atrial contractions, premature ventricular contractions, ventricular tachycardia, Wolff-Parkinson-White syndrome

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

What is examples of class Ib drugs

A

tocainide, mexiletine, phenytoin, lidocaine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does class Ib drugs block sodium channels

A

Accelerate repolarization

Decrease the action potential duration

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

What are class Ib drugs used for

A

ventricular dysrhythmias only (premature ventricular contractions, ventricular tachycardia, ventricular fibrillation)

Digoxin toxicity

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

What is examples Ic drugs

A

encainide, flecainide, propafenone

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

What is Ic drugs affect onaction potential duration or repolarization

A

Little effect

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

What class 1 drug is the stronger sodium channel blocker

A

class Ic

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

What is class Ic drug used for

A

Used for severe ventricular dysrhythmias

May be used in atrial fibrillation/flutter

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

What are class II drugs, and how do they work

A

Beta blockers

Reduce or block sympathetic nervous system stimulation, thus reducing transmission of phase 4 depolarisation of impulses in the heart’s conduction system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is examples of class II drugs

A

atenolol, bisoprolol, propranolol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is the use of class 11 drugs

A

General myocardial depressants for both supraventricular and ventricular dysrhythmias

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is first line use for atrial fibrillation

A

Class II - bisoprolol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How does class III prolong refractoriness

A

Increase action potential duration by prolonging repolarization in phase 3
Slowing the rate pottasium coming out the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is examples of class III drugs

A

amiodarone, bretylium, sotalol,

25
Q

When is class III drugs used

A

Used for dysrhythmias that are difficult to treat

Life-threatening ventricular tachycardia or fibrillation, atrial fibrillation or flutter—resistant to other drugs

Sustained ventricular tachycardia

26
Q

How does class IV drugs acts as calcium channel blockers

A

By depressing phase 4 depolarization

27
Q

What is examples of class IV drugs

A

verapamil, diltiazem

28
Q

What are class IV drugs used for

A

paroxysmal supraventricular tachycardia; rate control for atrial fibrillation and flutter

29
Q

What is examples of antidysrhythmics

A

Digoxin

adenosine

30
Q

What kind of drug is digoxin and whats it affect on the heart

A

Cardiac glycoside
Positive ionotrope

Improves strength of cardiac contraction

31
Q

How does digoxin affect the hearts contractility

A

Inhibits the sodium-potassium ATPase pump

Allows more calcium to be available for contraction

32
Q

What is digoxin used for

A

Used for heart failure and atrial dysrhythmias

33
Q

What is the disadvantages of digoxin used

A

Low therapeutic jinxed therefore drug levels must be monitored for toxicity

34
Q

What patient in digoxin commonly used in and why

A

Commonly used in elderly, as digoxin has a reduced globular filtration rate, therefore as elderly more likely to have renal impairment its more beneficial

35
Q

What is the side affect of digoxin toxicity

A
Nausea and vomiting
Xanthopsia
Bradycardia
Tachycardia
Arrhythmias: VT and VF
36
Q

What is the problem in treating digoxin toxicity

A

Long half life
not effectively removed by dialysis
Half life increased in renal impairment

37
Q

What is the treatment plan in digoxin toxicity, and what is the further treatment plan if levels are high with a risk of arrhythmia

A

Stop digoxin

Give digibind
-Digoxin immune antibody
Binds with digoxin, forming complex molecules
Excreted in urine

38
Q

When are digoxin toxicity more serious

A

if potassium levels are low

risk of developing arrhythmia

39
Q

What is the side effect of the drug interaction between digoxin and amiodarone (class II drug)

A
Thyroid (hypo or hyperthyroidism)
Pulmonary fibrosis
Slate – grey pigmentation
Corneal deposits
LFT abnormalities
40
Q

How does the antidysrhythmics adenosine affect the heart rate

A

Slows conduction through the AV node

41
Q

What is adenosine used for

A

to convert paroxysmal supraventricular tachycardia to sinus rhythm

42
Q

How is adenosine administrated

A

administered as fast IV push

43
Q

What is the side effect of adenosine

A

May cause asystole for a few seconds, other side effects minimum

(very short half life)

44
Q

Whats is one of the main side effects of antiarrhythmics

A

arrhythmias

45
Q

What is the treatment for sinus tachycarida

A

Class II - beta blockers

Class IV - calcium channel blockers

46
Q

what is the treatment for atrial fibrillation/flutter

A

Class IA, IC, -sodium channel blockers
Class II - Beta blocker
Class III - prolong refractoriness
Class IV - calcium channel blockers

Anticoagulation

47
Q

What is the treatment for Paroxysmal supraventricular tachycardia

A

Class IA/ IC, - sodium channel blockers II,
Class III, prolong refractoriness
Class IV, - calcium channel blockers

adenosine - decreases HR

48
Q

What is the treatment for AV block

A

atropine

49
Q

What is the treatment for ventricular tachycardia

A

Class I - sodium channel blockers
Class II - Beta blcokers
Class III - prolong refractoriness

50
Q

Why it is wise to give anticoagulation with atrial fibrillation

A

As increase risk of stroke and peripheral emboli

51
Q

What is examples of anticoagulation drugs

A

Warfarin
- Structurally related to vitamin K therefore Inhibits production of active clotting factors

Dabigatran/Apixaban
- direct thrombin inhibitor

Rivaroxaban
- Factor Xa inhibitor
Preventing the formation of thrombin

52
Q

What is the indications of anticoagulation therapy

A

Atrial fibrillation - reduce stroke risk by 80%

DVT/PE

After surgery

Immobilisation: those at high risk of DVT

53
Q

What are the drugs that interact with warfarin and increase activity and how

A

Aspirin, Sulfonamides - decrease binding to albumin

Cimetidine, Disulfiram - inhibit degradation

Antibiotics (oral) - decrease synthesis of clotting factors

54
Q

What are the drugs that interact with warfarin and promote bleeding

A

Aspirin - Inhibition of platelets

antimetabolites + heparin - Inhibition of clotting factors

55
Q

What are drugs that interact with warfarin and decrease activity

A

Barbiturates + pheytoin
= Induction of metabolizing
Enzymes (cytochrome P450)

Vitamin K - promote clotting factor synthesis

Cholestyramine - reduced absorption

56
Q

Where is warfarin metabolised and how is the therapy monitored

A

In the liver by the cytochrome P450 system

International normalised ratio (INR)
=Standard thromboplastin time

Normal INR = 1

educate patients
watch alcohol intake

57
Q

What do you give first in the indication of DVT

A

Heparin

58
Q

What is the disadvantages to warfarin therapy

A

Can promote Bleeding
Is a tetraogenic
- chondrodysplasia - malformation of cartilage

59
Q

Wha conditions increases you risk of bleeding on warfarin

A
C - congestive heart failure 
H - hypertension 
A - age > 75 years 
D - diabetes mellitus 
S - stroke (or TIA) 

CHADS2