Pharmacology of Antiarrhythmics I Flashcards Preview

CV II Exam 3 > Pharmacology of Antiarrhythmics I > Flashcards

Flashcards in Pharmacology of Antiarrhythmics I Deck (55):
1

procainamide

class Ia Na channel blocker

2

lidocaine

class Ib Na channel blocker

3

flecainide

class Ic Na channel blocker

4

class II antiarrhythmics

esmolol
metoprolol
propranolol

5

amiodarone

class III - K channel blocker

6

sotalol

class III - K channel blocker

7

verapamil and diltiazem

class IV - non-DHP CCB antiarrhythmics

8

ACLS drugs

adenosine
atropine
MgSO4

9

sodium gradient

both inside drive

10

potassium gradient

concentration outward
electrical inward

11

m gates

activation gates Na

12

h gates

inactivation gates Na

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rapid depolarization

phase 0
Na perm increase

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brief repolarization

phase 1
K efflux
Ca moves in

15

plateau phase

phase 2
Ca influx and K efflux

16

repolarization

phase 3
K efflux

17

gradual depolarization

phase 4
Na leak balanced by K efflux

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SA node

Na current (fast)

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AV node

Ca current (slow)

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early afterdepolarization

interrupt phase 3

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delayed afterdepolarization

interrupts phase 4

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4 ways antiarrhythmics work

1 decreased phase 4 slope
2 increased threshold
3 increased max diastolic potential
4 increased action potential duration

23

class Ia

-intermediate kinetics
-decreased conduction velocity
-slow phase 0 depolarization
-increased refractoriness
-decreased autonomics

24

class Ib

-rapid kinetics
-shorten phase 3 repolarization
-no effect velocity

25

class Ic

-slow kinetics
-slow phase 0
-decreased conduction velocity
-no effect on refractoriness

26

class II

beta blocker
-prolonged AV conduction
-decrease conduction velocity
-increased refractoriness
-decreased autonomics
-decreased HR and contractility
-decreased O2 demand

27

class III

K channel blockers
-prolong phase 3 repolarization
-diminshed outward K during repolarization
-increased refractoriness
-increased AP duration

28

class IV

Ca channel blockers
-slow phase 4 depolarization and slow conduction in tissues dependent on Ca current (AV node)
-decreased conduction velocity
-increased refractoriness
-decreased autonomics

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atrial and ventricular arrhythmias

procainamide - class Ia

30

DOC for termination of VT and prevention of VF after cardioversion

lidocaine - class Ib

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supraventricular arrhythmias

felcainide - class Ic

32

tachyarrhythmias, AF, Afib, AV node re-entrant tachycardia, HTN, HF, IHD

beta blockers - class II

propranolol - nonselective
metoprolol - selective
esmolol - selective, fast

33

AFib, recurrent VT, adjunct to ICD to reduce uncomfortable discharges

amiodarone - class III - K blocker

long half life

34

amiodarone

class III - K blocker
-accumulate in heart
-drug interactions

increases levels of statins, digoxin, warfarin**

35

cimetidine

increases amiodarone levels
-CPY3A4 blockers

36

rifampin

decreases amiodarone levels
-CYP3A4 inducer

37

SVT, decrease ventricular rate in Afib and AF, angina, HTN

verapamil
non-DHP CCBs
-class IV

38

constipation

verapamil

39

SVT, angina, HTN

diltiazem

class IV

40

conversion of paroxysmal SVT

adenosine

activates inward rectifier K current and inhibits Ca current
-hyperpolarization and increased refractory

41

atropine

bradycardia, neuromuscular blockade reversal, cholinergic poisoning

blocks action of ACh at PS sites
-increased CO

42

magnesium

digitalis induced arrhythmia

TdP

43

Afib, SVT, HF

digoxin

44

work only on ventricualr tissue

class Ib

45

never after MI or with CHF or LVH

class Ic

46

increased risk of TdP

class Ia and III

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decrease heart rate

class II and IV

48

acute AFib

IV CCB
BB
digoxin

49

chronic AFib

oral BB
CCB

50

Tx of AFib

rate control > rhythm control
-and anticoag

51

most effective cardioversion

direct current (electrical)

52

paroxysmal supraventricular tachycardia

IV adenosine (acute)

catheter ablation (chronic)

AV nodal reentry

53

PVCs after MI

first 24 hours
-beta-blockers

54

sustained V tach

hemo unstable - cardioversion
stable - procainamide

55

torsades

hemo unstable - electrical cardioversion

hemo stable - MgSO4