Pharmacology of Antiarrhythmics I

Question 1

procainamide

Answer 1

class Ia Na channel blocker

Question 2

lidocaine

Answer 2

class Ib Na channel blocker

Question 3

flecainide

Answer 3

class Ic Na channel blocker

Question 4

class II antiarrhythmics

Answer 4

esmolol
metoprolol
propranolol

Question 5

amiodarone

Answer 5

class III - K channel blocker

Question 6

sotalol

Answer 6

class III - K channel blocker

Question 7

verapamil and diltiazem

Answer 7

class IV - non-DHP CCB antiarrhythmics

Question 8

ACLS drugs

Answer 8

adenosine
atropine
MgSO4

Question 9

sodium gradient

Answer 9

both inside drive

Question 10

potassium gradient

Answer 10

concentration outward

electrical inward

Question 11

m gates

Answer 11

activation gates Na

Question 12

h gates

Answer 12

inactivation gates Na

Question 13

rapid depolarization

Answer 13

phase 0

Na perm increase

Question 14

brief repolarization

Answer 14

phase 1
K efflux
Ca moves in

Question 15

plateau phase

Answer 15

phase 2

Ca influx and K efflux

Question 16

repolarization

Answer 16

phase 3

K efflux

Question 17

gradual depolarization

Answer 17

phase 4

Na leak balanced by K efflux

Question 18

SA node

Answer 18

Na current (fast)

Question 19

AV node

Answer 19

Ca current (slow)

Question 20

early afterdepolarization

Answer 20

interrupt phase 3

Question 21

delayed afterdepolarization

Answer 21

interrupts phase 4

Question 22

4 ways antiarrhythmics work

Answer 22

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

Question 23

class Ia

Answer 23

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

Question 24

class Ib

Answer 24

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

Question 25

class Ic

Answer 25

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

Question 26

class II

Answer 26

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

Question 27

class III

Answer 27

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

Question 28

class IV

Answer 28

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

Question 29

atrial and ventricular arrhythmias

Answer 29

procainamide - class Ia

Question 30

DOC for termination of VT and prevention of VF after cardioversion

Answer 30

lidocaine - class Ib

Question 31

supraventricular arrhythmias

Answer 31

felcainide - class Ic

Question 32

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

Answer 32

beta blockers - class II propranolol - nonselective metoprolol - selective esmolol - selective, fast

Question 33

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

Answer 33

amiodarone - class III - K blocker long half life

Question 34

amiodarone

Answer 34

class III - K blocker - accumulate in heart - drug interactions increases levels of statins, digoxin, warfarin**

Question 35

cimetidine

Answer 35

increases amiodarone levels | -CPY3A4 blockers

Question 36

rifampin

Answer 36

decreases amiodarone levels | -CYP3A4 inducer

Question 37

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

Answer 37

verapamil non-DHP CCBs -class IV

Question 38

constipation

Answer 38

verapamil

Question 39

SVT, angina, HTN

Answer 39

diltiazem class IV

Question 40

conversion of paroxysmal SVT

Answer 40

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

Question 41

atropine

Answer 41

bradycardia, neuromuscular blockade reversal, cholinergic poisoning blocks action of ACh at PS sites -increased CO

Question 42

magnesium

Answer 42

digitalis induced arrhythmia TdP

Question 43

Afib, SVT, HF

Answer 43

digoxin

Question 44

work only on ventricualr tissue

Answer 44

class Ib

Question 45

never after MI or with CHF or LVH

Answer 45

class Ic

Question 46

increased risk of TdP

Answer 46

class Ia and III

Question 47

decrease heart rate

Answer 47

class II and IV

Question 48

acute AFib

Answer 48

IV CCB BB digoxin

Question 49

chronic AFib

Answer 49

oral BB | CCB

Question 50

Tx of AFib

Answer 50

rate control > rhythm control | -and anticoag

Question 51

most effective cardioversion

Answer 51

direct current (electrical)

Question 52

paroxysmal supraventricular tachycardia

Answer 52

IV adenosine (acute) catheter ablation (chronic) AV nodal reentry

Question 53

PVCs after MI

Answer 53

first 24 hours | -beta-blockers

Question 54

sustained V tach

Answer 54

hemo unstable - cardioversion | stable - procainamide

Question 55

torsades

Answer 55

hemo unstable - electrical cardioversion hemo stable - MgSO4