Antiarryhthmics

Question 0

Quinidine Adverse

Answer 0

Class 1 Sodium channel blocker
**Cinchonism (named after tree that anti malarials come from-Quinines-so seen in any antimalarials only BUZZ WORD) - Tinnitus, ocular dysfunction (cannot tell if miosis or mydriasis because it is both a muscarinic and alpha blocker), CNS excitation, GI disturbances (same as eyes explanation)
Hypotension
Prolongation of QRS and QT interval - Torsades *****

Question 1

Quinidine General

Answer 1

Class IA Sodium channel blocker

• muscarinic receptor blocker
• alpha bloc (possible reflex tachycardia)
• wide clinical use in many arrhthymias; in atrial fibrillation, need initial digitalization (to slow AV conduction)

Question 2

Quinidine drug interactions

Answer 2

Class 1 sodium channel blocker

• Hyperkalemia enhances effects and vice versa
• Displaces digoxin from tissue binding sites

Question 3

Procainamide Description

Answer 3

Class 1A Sodium channel blocker

• Less muscarinic receptor block than quinidine
• Metabolized through conjugation by N-acetyltransferase
• -therefore affected by slow/fast metabolizers

Question 4

Procainamide Adverse

Answer 4

Class 1 Sodium channel blockers
SLE like syndrome
Hematotoxicity
CV effects (torsades)

Question 5

Torsades caused by what type of drugs?

Answer 5

Anti muscarinic

Question 6

SLE like syndrome is caused by what drugs?

Answer 6

Procainamide
Hydralazine (anti HTN)
Isoniazid (anti TB)
-seen in slow acetylators

Question 7

Drug induced SLE lab results

Answer 7

Positive anti ANA
Positive anti histone** (specific to drug induced)
Negative anti dsDNA

Question 8

Disopyramide

Answer 8

Class 1A sodium channel blocker

Question 9

Class 1B Drugs

Answer 9

Sodium channel blockers
-Block fast sodium channels (decrease
-Block inactivated channels (slow conduction in hypoxic and ischemic heart) -slows cells ability to go back to resting
-Decrease APD - due to block of the slow sodium “window” currents
Lidocaine, Mexiletine

Question 10

Lidocaine cardio uses

Answer 10

Class1 B

• post MI
• Open heart surgery
• Digoxin toxicity*

Question 11

Lidocaine adverse

Answer 11

Class 1B
CNS toxicity (seizures); least cardiotoxic of conventional anti arrhythmics
***IV only*** (due to first pass metabolism)

Question 12

Mexiletine and Tocainide

Answer 12

Class 1B drugs
Same as lidocaine
Oral formulations

Question 13

Class 1C

Answer 13

Second choice drug (only use if nothing else worked)

• block fast sodium channels especially His-Purinje tissue
• No effect on APD
• No ANS effect

Question 14

Flecainide

Answer 14

Class 1C
Limited use becase of its proarrhthymic effects leading to sudden cardiac death
Last ditch drug … some will be saved but many may die too
Flecainide, Propafenone

Question 15

Class II

Answer 15

Beta blockers (see ANS)

• decrease SA and AV nodal activity (parasymp dominance)
• decrease slope of phase 4

Question 16

Class II Drugs

Answer 16

Beta blockers 
Non selective  (propranolol) and selective (acebutolol, esmolol)

Question 17

Class II Uses

Answer 17

Beta blockers

• negative inotropic effect decreases O2 demand so helpful to reduce reccurence of MI or prevent MI in general
• Prophylaxis post MI, supraventricular tachyarrhythmias (SVT)
• Esmolol (IV) is used in acute SVTs

Question 18

Which beta blocker is used in treatment of acute supraventricular tachycardias but not for prophylaxis?

Answer 18

Esmolol

Question 19

Esmolol is indicated for use in what?

Answer 19

Supraventricular tachycardia

Indicated for the rapid control of supraventricular tachycardias in patients with atrial fibrillation or atrial flutter in the peri or post operative setting where rapid, short term control of ventricular rate with an ultra short acting agent is indicated

Question 20

The beta blockers have what as part of their antiarrhythmic mechanism of action?

Answer 20

Decrease cAMP levels

Question 21

A patient is diagnosed with congenital long QT syndrome. If this patient is to be treated for cardiac arrhthymias, drugs with which mechanism would most likely be contraindicated?

Answer 21

Block potassium channels would be contraindicated
Congenital long QT syndrome predisposes patients to torsades, therefore those individuals should avoid drugs that May also precipitate torsades.  Both class 1A and Class III antiarrhythmic drugs may cause torsades because of their potassium channel blocking ability

Question 22

A patient on antiarrhthymic drug therapy yexperiences syncopal episodes associated with a prolonged QT interval. The patient also suffers from diarrhea and gastrointestinal upset and complains of ringing in his ears. What drug was prescribed for this patient?

Answer 22

Quinidine
Torsades-K channel blocks
Cinchonism- quinines

Question 23

Which antiarrhythmic drug is associated with an increase in mortality when usedprophylactically in ventricular tachycardia?

Answer 23

Flecainide

Class 1C antiarrhthymics -increased sudden death post MI

Question 24

What Class 1 oral drugs preferentially target ischemic areas of the heart?

Answer 24

Class 1B Mexiletine and Tocainide Lidocaine is only IV

Question 25

``` Compared with procainamide, which of the following effects is unique to quinidine? Hypotension Prolongation of the action potential Sodium channel block Systemic lupus erythematosus Torsades ```

Answer 25

Hypotension

Question 26

Class IA Mechanism

Answer 26

-Block fast sodium channels -Preferentially in the ***open*** or activated state -Increase APD and ERP -Also block potassium channel (prolongs repolarization) Quinidine, Procainamide, Dispyramide

Question 27

Class III Mechanism

Answer 27

Potassium channel blockers -decreased I(k), slowing phase 3 -increase APD and ERP Amiodarone, Ibutilide, Dofetilde, Sotalol "AIDS"

Question 28

Amiodarone general

Answer 28

``` Class III Potassium Blocker Mimic classes I, II, III and IV Increases APD and ERP in all cardiac tissues Use-any arrhythmia half life - greater than 80 days ```

Question 29

Amiodarone Side effects

Answer 29

High tissue and protein binding - Pulmonary fibrosis (restrictive pulmonary disease) - Blue pigmentation of the skin (smurf) - photo toxicity - corneal deposits - hepatic necrosis - thyroid dysfunction

Question 30

Sotalol

Answer 30

Decreases I(k), slowing phase III Beta one blockade, leading to decrease heart rate, decrease AV conduction Use-life threatening ventricular arrhythmia

Question 31

If a patient is prescribed sotalol for treatment of an arrhythmia, he was most likely diagnosed with what?

Answer 31

Ventricular fibrillation

Question 32

A patient with recurrent supraventricular tachycardia is started on a new medication that has a risk of causing pulmonary fibrosis. What drug?

Answer 32

Amiodarone

Question 33

The class III antiarrhythmics primarily slow what phase?

Answer 33

3

Question 34

Class IV

Answer 34

L type Calcium channel blockers - block slow cardiac Ca2+ channels - decrease phase 0, decrease phase IV - decrease SA, decrease AV nodal activity

Question 35

Class IV drugs

Answer 35

Calcium channel blockers | Verapamil and diltiazem

Question 36

Verapamil and Diltiazem Use

Answer 36

Supraventricular tachycardias

Question 37

Verapamil and Diltiazem Side effects

Answer 37

****VERAPAMIL CONSTIPATION****** | AV block

Question 38

Verapamil and Diltiazem Drug Interactions

Answer 38

- Additive AV block with beta blockers, digoxin | - Verapamil displaces digoxin from tissue binding sites

Question 39

If a patient is prescribed verapamil for an arrhythmia she most likely has what?

Answer 39

Paroxysmal supraventricular tachycardia

Question 40

Diltiazem effects what phase as an antiarrhythmic?

Answer 40

Decreases phase 4

Question 41

Adenosine is antagonized by what?

Answer 41

Methylxanthines - theophylline (used in COPDs like asthma which can cause V-tach) and caffeine

Question 42

Magnesium is used for what?

Answer 42

Torsades

Question 43

Drugs that cause Torsades

Answer 43

Potassium channel blockers Antimuscarinics -quinidine, antihistamines Antipsychotics (Thioridazine) Tricyclic antidepressants

Question 44

Magnesium works how?

Answer 44

By antagonizing calcium