Antiarrhythmic Drugs- Exam 3

Question 1

**What is happening at each of the boxes? What type of cell?

Answer 1

blue: Na coming IN

red: Ca coming IN

purple: K leaving

cardiac pacemaker cell

Question 2

**What phase is happening at each colored box?

Answer 2

blue: phase 4: slow Na coming IN- depolarization

red: phase 0: rapid Ca coming IN- depolarization

purple: phase 3: K leaving and cell repolarization

Question 3

**What phase number does each colored circle represent?

Answer 3

yellow: 4

red: 0

green: 1

blue: 2

pink: 3

yellow: 4

Question 4

**What is happening at each number phase 4, 0, 1, 2, 3, 4?

Answer 4

4: K

0: rapid Na IN

1: K and Cl out

2: Ca IN and K out

3: K out

Question 5

** When Ca is blocked, the electrical conduction is (longer/shorter)

Answer 5

block Ca and the electrical conduction takes LONGER

Question 6

The aim of therapy of the arrhythmias is to ______ activity and modify conduction or refractoriness in _____ to disable ______

Answer 6

reduce ectopic pacemaker

reentry circuits

circus movement

Question 7

Antiarrhythmic drugs decrease the _____ of _______ more than that of the _____. They also reduce _______ and ______ and increase the _______ to a greater extent in depolarized tissue than in normally polarized tissue

Answer 7

automaticity

ectopic pacemakers

SA node

conduction

excitability

refractory period

Question 8

How are AAD classified? What are the different drug classes?

Answer 8

Vaughan-Williams Classification system

Class I-IV

class I: drugs that block fast sodium channels
class II: BB
class III: block potassium channels
class IV: calcium channel blockers

Question 9

Maybe consider looking at this summary table again??

Answer 9

Question 10

What drug class?

quinidine, procainamide, disopyramide

Answer 10

Class Ia

Question 11

what drug class? slow the rate of rise of the action potential and prolong its duration, thus slowing conduction and increasing refractoriness (moderate depression of phase 0 upstroke of the action potential)

Answer 11

class Ia: quinidine, procainamide, disopyramide)

Question 12

What drug class?

lidocaine, mexiletine

Answer 12

class Ib agents

Question 13

what drug class? shorten action potential duration; they do not affect conduction or refractoriness (minimal depression of phase 0 upstroke of the action potential)

Answer 13

class Ib agents: lidocaine, mexiletine

Question 14

What drug class?

flecainide, propafenone

Answer 14

Class Ic agents

Question 15

What drug class? Dissociates from channel with slow kinetics (no change in action potential duration)

Answer 15

class Ic: (flecainide, propafenone)

Question 16

How are the class I drugs further subdivided?

Answer 16

Three subclasses are further defined by the effect of the agents on the Purkinje fiber action potential:

Question 17

What drug class does this represent?

Answer 17

class Ia

Question 18

What drug class does this represent?

Answer 18

class Ib

Question 19

What drug class does this represent?

Answer 19

class Ic

Question 20

______ has potent anticholinergic properties that affect the SA and AV nodes, which can increase the SA nodal discharge rate and AV nodal conduction. What does it lead to?

Answer 20

quinidine

This may lead to increased ventricular rates with afib or aflutter

Question 21

**What also needs to be prescribed concurrently with quinidine? What drug class?

Answer 21

Addition of a beta blocker, non-dihydropyridine CCB, or digoxin protects against increased ventricular rates with afib or aflutter

Ia

Question 22

quinidine can also lead to ______ and interacts with ______

Answer 22

torsades

CYP3A4 inducers or inhibitors

Question 23

_____ is similar to quinidine but without the anticholinergic effects.

Answer 23

procainamide

Question 24

procainamide also carries a risk of ______ because of ______. What are the SE?

Answer 24

torsades

prolongs the QT interval

SLE like s/s- MC adverse effect

Question 25

_______ is a potent anticholinergic and negative inotropic effects limits uses clinically. When is it used clinically?

Answer 25

Disopyramide (Norpace) hypertrophic cardiomyopathy

Question 26

Disopyramide (Norpace) also increases risk of ______ due to _______. When is it CI?

Answer 26

Prolongs QT, increasing risk of torsades Contraindicated in patients with reduced LV EF (<40%)

Question 27

What are the adverse events associated with Disopyramide (Norpace)?

Answer 27

Precipitation of CHF Anticholinergic effects – dry mouth, urinary retention, constipation, blurred vision

Question 28

______ is selective to ischemic tissue, and especially to active fast sodium channels in the bundle of HIS, Purkinje fibers, and ventricular myocardium. What drug class?

Answer 28

lidocaine class Ib

Question 29

How is lidocaine administered? What is the typical pt?

Answer 29

continuous IV infusion following an MI need to check levels because it can be toxic especially in pts with liver failure

Question 30

What are the adverse effects of lidocaine?

Answer 30

CNS effects: dizzy, paresthesia, disorientation, tremor etc etc

Question 31

_______ is similar to lidocaine but in oral form. What drug class?

Answer 31

Mexiletine class Ib

Question 32

_______ can be used in combination with class IA and III drugs for the treatment of refractory ventricular dysrhythmias. NOT as a single agent

Answer 32

mexiletine

Question 33

What are the SE of mexiletine?

Answer 33

GI and neuro SE

Question 34

________ slows conduction velocity in the Purkinje fibers and the AV node. May lengthen PR interval and QRS duration. What drug class? When is it commonly used?

Answer 34

Flecainide (Tambacor) class Ic afib/flutter

Question 35

What kind of pt is Flecainide (Tambacor) and Propafenone (Rythmol) good for? Why?

Answer 35

MUST have a structurally normal heart!! no hypertrophy, valvular dz or ischemia high risk of vent tachy in pts without normal hearts

Question 36

Blurred vision, dizziness, headache, tremor, N/V

Answer 36

What are the SE of Flecainide (Tambacor)?

Question 37

_______ slows conduction velocity in the Purkinje fibers and the AV node; also has a mild nonselective beta blocking effect May lengthen PR interval and QRS duration, leading to conduction disturbances such as bradycardia and heart block. What drug class?

Answer 37

Propafenone (Rythmol) class Ic

Question 38

Propafenone (Rythmol) may _____ PR interval and ____ duration, leading to ______ disturbances such as ______ and heart block. When is it commonly used?

Answer 38

lengthen QRS conduction bradycardia afib/flutter

Question 39

Blurred vision, dizziness, headache, N/V, bronchospasm, and taste disturbances METALLIC TASTE

Answer 39

What are the SE of Propafenone (Rythmol)?

Question 40

______ decrease automaticity, prolong AV conduction, and prolong refractoriness. Negative chronotropic and inotropic effects. What drug class?

Answer 40

Beta Blockers class II

Question 41

What BB is used MC in arrhythmias? how? ______ can be used as a continuous IV infusion for rapid afib/flutter

Answer 41

Metoprolol given in IV bolusus NOT continuous drip Esmolol

Question 42

_____ are useful in suppressing ventricular dysrhythmias, as well as supraventricular dysrhythmias. Especially helpful when used in COMBO with other AAD

Answer 42

Beta blockers

Question 43

_______ block POTASSIUM channels and _____ repolarization, widening the QRS and prolonging the QT interval. Decrease automaticity and conduction and prolong refractoriness

Answer 43

class III prolong

Question 44

Avoid concomitant use of _____ with other drugs that can ______ to minimize the risk of torsades

Answer 44

class III AADs prolong the QT interval

Question 45

NEVER use class III AAD with ______ due to _____

Answer 45

class Ia : quinidine, procainamide, disopyramide) risk of torsades

Question 46

What are the 4 class characteristics that amiodarone processes?

Answer 46

Primarily a potassium channel blocker, but also blocks sodium channels, has non-selective beta blocking activity, and has weak calcium channel blocking properties Works on all cardiac cells (SA node, AV node, atria, ventricles and Purkinjes)

Question 47

amiodarone has minimal to no _____ effects and can safely be used in patients with ______

Answer 47

no negative inotropic effects LV dysfunction

Question 48

What is the generic dosing for amiodarone? What kind of heart pt is amiodarone good for?

Answer 48

start amiodarone dosing at HIGH levels then go down good for structurally weak hearts

Question 49

_______ is an uncommon, but possibly life-threatening adverse event of amiodarone. What is the screening?

Answer 49

Pulmonary toxicity annual chest xrays, if fibrosis is seen on xray need to stop amiodarone immediately

Question 50

_____ is also a common SE of amiodarone. why? what is the monitoring?

Answer 50

thyroid problems: hypo give synthroid hyper-> need to stop immediately because amiodarone is 38% iodine by weight obtain baseline TSH and repeat q6 months while the pt is taking it

Question 51

amiodarone can also build up in the eyes causing ____ and _____. What is the screening?

Answer 51

corneal and lens opacities annual eye exams

Question 52

What derm reactions are possible with amiodarone?

Answer 52

blue/gray skin and photosensitivity

Question 53

What are the monitoring requirements for a pt on amiodarone?

Answer 53

pulm toxicity -> annual chest xray TSH at baseline and Q6 months yearly eye exam GI: liver toxicity -> screening LFTs every 6 months neuro: tremor, ataxia, fatigue, insomnia derm: photosensitivity and blue/gray skin discoloration, need to wear sunscreen

Question 54

amiodarone is also a potent inhibitor of _______. Potentiates the effects of ______ and can double serum ______ concentrations

Answer 54

CYP3A4 enzymes warfarin digoxin

Question 55

______ A class III AAD that also has nonselective beta-adrenergic blocking properties. May decrease cardiac contractility and therefore should be avoided in patients with LV dysfunction

Answer 55

Sotalol (Betapace)

Question 56

QT prolongation is common with _______ and should be monitored for closely. Discontinue if QT interval _______. Avoid combining with other QT prolonging drugs

Answer 56

Sotalol (Betapace) is a potassium channel blocker greater 550 ms

Question 57

_______ is a potassium channel blocker that does NOT have any BP lower effects and must be given at the same time everyday. What are the SE?

Answer 57

Sotalol (Betapace) tired, sluggish

Question 58

_______ results in a prolonged action potential and an increased QT interval. Affects the ____ more than the ______ No negative inotropic effects, therefore is safe to use in patients with LV dysfunction

Answer 58

Dofetilide (Tikosyn) atria ventricles

Question 59

What is the main concern for pts taking Dofetilide (Tikosyn)? What is the monitoring?

Answer 59

torsades de pointes Patients should be in the hospital, on telemetry with Q12 hour EKG’s for first 3 days of loading Tikosyn to monitor QT interval and adjust dose

Question 60

What 6 medications are CI with concurrent use of Dofetilide (Tikosyn)?

Answer 60

cimetidine ketoconazole megestrol prochlorperazine Bactrim verapamil

Question 61

Need to avoid Dofetilide (Tikosyn) and ________ and cleared ______ so do not use in patients _______

Answer 61

inhibitors of the CYP3A4 isoenzyme renally so do not use in patients with CrCl < 20 mL/min

Question 62

_____ is considered it the “safe cousin of amiodarone”; but not nearly as effective, and side effects and toxicities are still common. What drug class?

Answer 62

Dronedarone (Multaq) class III

Question 63

dronedarone has very simliar SE profile to amiodarone except _______

Answer 63

dronedarone has NO effect on the thyroid still cannot use it in HF pts and those with bad livers

Question 64

_______ is structurally similar to sotalol, but no beta-blocking activity. What drug class?

Answer 64

Ibutilide (Corvert)

Question 65

** _____ is available only in IV form, and indicated only for afib/flutter cardioversion in the acute setting only. What is the major adverse effect? When should you NOT use it?

Answer 65

Ibutilide (Corvert) torsades Should be avoided in patients with LV dysfunction and electrolyte abnormalities (especially hypokalemia and hypomagnesemia)

Question 66

______ and ______ are the only CCB used in arrhythmias. What drug class?

Answer 66

Verapamil and Diltiazem class IV

Question 67

______ and _______ decrease automaticity and AV conduction and have potent negative inotrophic effects. Should be avoided in pts with LV dysfunction

Answer 67

verapamil and diltiazem class IV

Question 68

______ predominant AA effect is on the AV node. Inhibits Calcium currents in the AV node and activates acetylcholine-mediated K+ currents in the atrium

Answer 68

Digoxin

Question 69

______ is mainly used for slowing the ventricular rate in afib/flutter, as well as terminating reentrant arrhythmias involving the AV node

Answer 69

digoxin

Question 70

What are the changes seen on EKG when a pt is on digoxin?

Answer 70

PR prolongation and ST segment depression

Question 71

What are 2 important things to note about digoxin?

Answer 71

intestinal microflora may metabolize digoxin so if pt is taking abx, pt is at risk for toxicity because of the lack of intestinal microflora metabolizing digoxin digoxin has a slow distribution to effector sites so need a higher IV loading dose to begin

Question 72

What should you do if your pt is taking digoxin and is renally impaired? What is the half life?

Answer 72

Renal elimination accounts for 80%, therefore doses should be reduced or dosing interval increased with renal insufficiency half life is 36 hours

Question 73

Amiodarone, quinidine, verapamil, diltiazem, itraconazole, propafenone, and flecainide (increase/decrease) digoxin clearance. so the dose need to be (increased/decreased) if combining with any of these drugs

Answer 73

decrease digoxin clearance so dose needs to be decreased if combined with any of these drugs

Question 74

Visual disturbances, dizziness, weakness, N/V/D, anorexia What am I? What should you do next?

Answer 74

digoxin toxicity IV hydration, electrolyte correction AND Digoxin immune Fab (digoxin reversal agent)

Question 75

What are some factors that can contribute to a digoxin toxicity?

Answer 75

declining/poor renal function electrolyte abnormalities hypoxia drug interactions

Question 76

_______ ACTIVATES potassium channels and by increasing the outward potassium current hyperpolarizes the membrane potential, decreasing spontaneous SA nodal depolarization. When is it commonly used?

Answer 76

adensosine Used for converting SVT to sinus rhythm; essentially causing sinus arrest

Question 77

What is the 1/2 life of adenosine? What are some SE?

Answer 77

VERY SHORT so the sinus arrest does NOT last long Chest discomfort, dyspnea, flushing, and headache

Question 78

______ A parasympatholytic drug that enhances both sinus nodal automaticity and AV nodal conduction through direct vagolytic action. Blocks acetylcholine at parasympathetic neuroeffector sites

Answer 78

atropine

Question 79

When is atropine used? What may it induce? What type of patient should you use it cautiously in?

Answer 79

emergent setting of SYMPTOMATIC bradycardia May induce tachycardia, which may result in poor outcomes in patients with MI, so use cautiously

Question 80

atropine has been reported to cause a paradoxical slowing of the heart rate when used in patients with _____ and ______. So monitor patient closely if using atropine in this setting

Answer 80

Mobitz type II AVB third degree AVB