Chapter 23: Cardiac Rhythm Flashcards Preview

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Flashcards in Chapter 23: Cardiac Rhythm Deck (46)
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1

MOA of Class IA Anti-arrhythmics

Block Na + channels
Block K+ channels
in ventricular myocytes
--> decreases conduction velocity thru myocardium

2

Class IA have what effect on AP duration, refractory period, and QT interval?

Increases all 3

3

Class IB effect on AP duration?

Decreases AP duration

4

What is Class IC MOA and effect of AP duration?

Marked (most) block of Na+ channels
Does not change AP duration

5

What are Class II drugs?

B-blockers...LOL!

6

MOA of Class III? Effect on AP duration, QT and refractory period?

K+ channel blockers

Increase AP duration
Increase refractory period
Increase QT interval

7

When do you use Class III?

When other anti-arrythmics fail

8

Class IV MOA? What do they do to conduction velocity, refractory period, and PR interval?

Ca2+ channel blockers

decrease conduction velocty
increase refractory
increase PR interval

9

Adenosine MOA?

opens G protein coupled K+ channel and suppress Ca dependent AP
--> increases K OUT of cell....suppress Ca AP

= inhibits SA node, atrial, and AV nodal conduction

10

Name the class IA drugs

quinidine
procainimide
disopyramide

11

Name the class IB drugs

Lidocaine
Mexiletine
Phenytoin

12

Name the class IC drugs

Flecainide
Propafenone

13

Name the class III drugs

Ibutilide
Dofetilide
Sotalol
Bretylium
Amiodarone
Dronedarone

14

Name the class IV drugs

Verapamil
Diltiazem

15

Quinidine toxicity?

cinchonism (impaired hearing, headache, dizziness)

16

Procainamide toxicity?

lupus like syndrome (almost all chronic users get this...think increase ANAs)

17

Disopyramide toxicity?

heart failure

18

All class IAs can cause what serious adverse effect?

Torsades des pointes

19

What should be used in conjunction with quinidine?

An agent that will slow AV nodal conduction
- Ca channel blocker or B blocker

20

What drug may be used in hypertrophic cardiomyopathy because it decreases cardiac contractility?

dispyramide

21

Quinidine induced ____ toxicity may occur in a fraction of patients

digoxin

22

What is the drug used to maintain normal sinus rhythm after conversion of atrial flutter?

procainamide

23

What is the class IA drug for paroxysmal supraventricular tachycardia? What if this fails?

quinidine (class IA)

if fails, try a class IC --> used as last resort drugs
= Flecainide or Propafenone

24

_____ suppresses purkinje automaticity without affecting the SA node

Lidocaine

25

Clinical use of lidocaine/mixiletine?

Ventricular arrythmias in context of MI, cardiac manipulation or cardiac glycosides

26

Class IB has an effect on what type of tissue?

INJURED/DISEASED myocardium

27

What drug is used for local anesthesia of skin or mucous membranes?

lidocaine

28

Clinical use of phenytoin?

tonic-clonic seizures

status epilepticus

non epileptic seizures

29

IB is Best ____
IC is Contraindicated _____

post MI
post MI/structural heart disease

30

What drugs are associated with excessive mortality and nonfatal cardiac arrest? (restrict these drugs to people who have failed other measures)

Class IC
= flecainide
propafenone

31

What type of drug would you give to decrease the likelihood for mortality and re-infarction after MI?

B blockers!

32

Ibutilide clinical use?

conversion of atrial fibrillation/atrial flutter to normal sinus rhythm

33

What must you do if giving ibutilide? Why?

monitor QT interval during administration

Bc 2% develop torsades des pointes and need cardioversion

34

Sotalol clinical use?

life threatening ventricular arrhythmias when patients can't tolerate amiodarone

35

Adverse effects of sotalol? So don't use in pts that have a hx of __?

bradycardia
bronchospasm --> dont use in pts with asthma!!

36

When v. arrythmias don't respond to lidocaine or defibb, what drug should you try?

Bretylium (no effect on atrial tissue)

37

What drugs targets the entire lipid membrane and can thus be considered a multi-class anti-arrhythmic?

amiodarone

38

Co-administration of amiodarone with what drug would decrease amiodarone levels?

phenytoin

39

Amiodarone toxicity?

severe pulmonary toxicity

thyroid dysfunction (40% iodine by weight)

Corneal deposits
Blue-gray skin discoloration
photosensitivity

40

Which of the class III drugs can cause torsades des pointes?

sotalol
ibutilide

41

Drug used for a fibb/a flutter that is similar to amiodarone, but has a shorter half life and less thyroid toxicity?

dronedarone

42

Don't use dronendarone in patients with what?

systolic heart failure!

43

What is the drug of choice for paroxysmal supraventricular tachycardia?

adenosine

44

Is adenosine short or long acting? What are the toxicities?

VERY short acting - 15sec

Facial flushing
Chest pressure
Diaphoresis

45

Do not use adenosine to treat ____

atrial fibb or atrial flutter

46

Ranolazine is used to treat ____

chronic angina pectoris

--> freq used in conjunction with nitrates or B blockers