Antiarrhythmias continued

Question 1

What class of antiarrhymics is good for atrial arrhythmias, what class of medications is this class

Answer 1

Class 2, beta-blockers

Question 2

What are the physiological effects of using beta-blockers for antiarrhythmias

Answer 2

Decreased sinus rate, increased PR-intervals, decrease phase 4 slope

Question 3

What is the main effect of using antiarrhythymics, effects on ECG

Answer 3

Potassium channel blocker, slowing the rate of depolarization and increasing the refactory period

Question 4

What are the primary class 3 AADs

Answer 4

Amiodarone, Dronedarone, Sotalol, Dofetillide

Question 5

Which class 3 AADs affect not only potassium channels but also sodium, calcium, and beta receptors as well, what effect would this have on an ECG

Answer 5

Amiodarone and Dronedarone/ decreased sinus rate, increased PR interval, increased QRS complex, increased QT interval

Question 6

Which class 3 AADs affect potassium and beta receptors

Answer 6

Sotalol

Question 7

Which class 3 AADs affect potassium channels only

Answer 7

Dofetillide

Question 8

T/F: Class 3 drugs are best used for maintaining normal sinus rhythm but not necessarily towards changing the sinus rhythm

Answer 8

True

Question 9

What does amiodarone inhibit, what are potential drug drug interactions with amiodarone

Answer 9

3A4, 2D6, 1A2, 2C9, P-GP/ Increase warfarin (cut by 25-50%), increase digoxin (cut by digoxin), increase simvastatin (max of 20 mg)

Question 10

What does dronaderone inhibit, what are potentail drug drug interactions

Answer 10

3a4, 2D6, p-gp/ increase digoxin concentrations 2.5 fold and increase simvastatin concentrations 4 fold (max 10 mg) with a substantial increase in dronaderone levels if taken with ketoconazole

Question 11

Due to the kinetics of amiodarone how does its effects change from minutes to days, hours to days, weeks to months

Answer 11

Mostly effects beta receptors and calcium but is not a large amount of change, effects on potassium channels start to rise altering sodium, major impact on potassium is apparent

Question 12

What is the loading dose for amiodarone, maintenance dose

Answer 12

400 mg TID with meals for 5 days then 400 mg per day for one month, 200 mg per day

Question 13

T/F: Amiodarone IV and Oral should never overlap each other so if a patient is switched to oral IV amiodarone should be D/C

Answer 13

True

Question 14

What are pertinent amiodarone side effects

Answer 14

corneal microdeposits/optic neuropathy, pulmonary fibrosis, liver toxicity

Question 15

What are cautious side effects of amiodarone

Answer 15

photosensitivity/skin discoloration, neuropathy/myopathy, hyper/hypothyroidism, proarrhythmia, bradycardia/heart block

Question 16

What is monoitored for amiodarone and how ofen are they checked

Answer 16

LFTs: every 6 months, TSH/TFTs: every 6 months, chest X-ray at baseline and every 12 months

Question 17

T/F: Dronedarone can be taken with or without food

Answer 17

False: Dronedarone should be taken WITH food to increase the bioavailability

Question 18

T/F: Dronedarone is not used as much as amiodarone because it does half as well

Answer 18

True

Question 19

What are contraindications of dronedarone

Answer 19

Patients with heart failure, permanent atrial fibrillation, liver dysfunction

Question 20

What drug has an interaction with dronedarone and has its dosing changed due to CrCl, how

Answer 20

Dabigatran/ CrCl 30-50 ml/min = dabigatran 75 mg twice daily, CrCl 15-30 ml/min = AVOID dabigatran

Question 21

Which class 3 drug is usually used if someone has heart failure, notable drug interactions

Answer 21

Dofetilide/ hydrochlorothiazide, verapamil, azoles, QT prolonging drugs

Question 22

T/F: Sotalol is also 100% renally excreted and for atrial fibraltion should not be used for a CrCl less than 40 and should not be used for a CrCl less than 10 for ventricular fibrillation

Answer 22

True

Question 23

What is the main concnern for sotalol, dofetilide

Answer 23

Bradycardia, Torsades de pointes

Question 24

What are the class 4 AADs, what is its physiological effect on ECG

Answer 24

Non-DHP calcium blockers, lowers sinus rate and increased PR-interval

Question 25

What alternative agent is used for AVNRT/AVRT to reduce condition in the AV node

Answer 25

Adenosine

Question 26

What is used to treat torsades de pointes

Answer 26

Magnesium

Question 27

T/F: Amiodarone should have a 3 month washout period before using other AADs

Answer 27

True

Question 28

What is a prolonged Qt interval that wouldn’t allow for dofetilide use, sobatol

Answer 28

Greater than 440 ms, greater than 450 ms