Anti-arrhythmics

Question 1

What is the cardiac pacemaker

Answer 1

SA node

Question 2

what is the cardiac gatekeeper

Answer 2

AV node

Question 3

how do anti-arrhythmic drugs work

Answer 3

affect specialized ion channels or affect sympathetic tone

Question 4

Ia MOA

Answer 4

moderate block of both open Na and K channels
slow phase 0 depolarization
prolong action potential and slow conduction

Question 5

Ia drugs

Answer 5

DQP: Disopyramide, Quinidine, Procainamide

Question 6

Ia uses

Answer 6

ventricular tachy-arrhythmias
Paroxysmal recurrent afib
Wolff-Parkinson-White syndrome (Procainamide)

Question 7

Ib MOA

Answer 7

mild blocking or inactivating sodium channels
shorten phase 3 repolarization
decrease duration of AP

Question 8

Ib drugs

Answer 8

LPM: Lidocaine, Phenytoin, Mexiletine

Question 9

Ib uses

Answer 9

ventricular tachycardias

Question 10

Ic MOA

Answer 10

block open Na channels

markedly slow phase 0 depolarization

Question 11

Ic drugs

Answer 11

FP: Flecainide

Propafenone (avoid in HF and MI)

Question 12

Ic uses

Answer 12

paroxysmal a-fib

Question 13

II MOA

Answer 13

block catecholamines
block AV node
decrease slope of phase 4 depolarization
prolong repolarization in AV node –> block reentry

Question 14

II drugs

Answer 14

Propranolol

Question 15

II uses

Answer 15

Tachyarrhythmia supraventricular

Question 16

III MOA

Answer 16

blocking IKr

prolong phase 3 repolarization without altering phase 0

Question 17

III drugs

Answer 17

Amiodarone
Sotalol
Ibutilide
Dofetilide (initiated in hospital, mandates testing every 3 months to check K, Mg, SCR and EKG)
Dronedarone

Question 18

III uses

Answer 18

Wolff-Parkinson-White syndrome (Sotalol)
Ventricular arrhythimias
atrial tachyarrhythmias

Question 19

IV MOA

Answer 19

block L-type calcium channels
decrease AV node conduction
increase refractory period
similar to class II but does not block adrenergic system

Question 20

IV drugs

Answer 20

Non-dihydrophyridine
CCBs
Verapamil
Diltiazem

Question 21

IV uses

Answer 21

prevent recurrence of paroxysmal supraventricular tachycardias
control ventricular rate in afib

Question 22

rate classes control rate?

Answer 22

Class II, IV

digoxin

Question 23

which classes control rhythm

Answer 23

Ia, c, III

Question 24

what are non-pharmacologic choices?

Answer 24

ablation

pacing

Question 25

DI's of Quinidine

Answer 25

warfarin | digoxin

Question 26

DI's of Disopyramide

Answer 26

glaucoma

Question 27

indications of Disopyramide

Answer 27

only paroxysmal supraventricular tachycardia

Question 28

CI of Mexiletine

Answer 28

3rd degree AV block

Question 29

indications of Mexiletine

Answer 29

ventricular arrhythmias | commonly as an add on to Amiodarone and not sole agent

Question 30

BB DI's

Answer 30

severe sinus bradycardia or heart block

Question 31

Amiodarone, Dronedarone, Sotalol, Dofetilide CI's

Answer 31

iodine hypersensitivity, hyperthyroidism, 3rd degree AV heart block (Dronedarone lacks iodine and therefore thyroid side effects)

Question 32

which class has the highest risk of proarrhythmias?

Answer 32

class I

Question 33

which class has anticholinergic effects?

Answer 33

IA

Question 34

Adenosine MOA

Answer 34

acts on adenosine receptors (GPCR) to decrease adenylyl cyclase to decrease cAMP

Question 35

side effect of Adenosine

Answer 35

transient hypotension and chest pain (within 15 seconds)

Question 36

Atropine MOA

Answer 36

competitieve inhibitor of muscarinic acetylcholine receptors

Question 37

indication of Atropine

Answer 37

bradycardia

Question 38

side effects of Atropine

Answer 38

blurry vision, dry mouth, tachycardia "dry as a bone, red as a beet, hot as a hare, blind as a bat, mad as a hatter"

Question 39

antidote to Atropine

Answer 39

Physostigmine

Question 40

Digoxin MOA

Answer 40

inhibit the Na/K ATPase in myocardium decrease membrane sodium gradient decrease sodium-calcium exchange increase intracellular calcium

Question 41

indications for Digoxin

Answer 41

Afib, atrial flutter with RVR, heart failure

Question 42

which anti-arrhythmics cause constipation

Answer 42

Verapamil and diltiazem