Arrhythmia Drugs

Question 1

Anti-Arrhythmic Drug Classes

Answer 1

Class I: Na+ channel blockade
Class II: B-adrenergic receptor blocker
Class III: K+ DRK channel blockers
Class IV: Ca+2 channel blockers

Question 2

Class I Subgroups

Answer 2

Class IA: moderate Na+ block (Increase in AP duration)
Class IB: mild Na+ block (Decrease in AP duration)
Class IC: marked Na+ block (No affect on AP)

Question 3

Class IA Effects

Answer 3

• Increase AP duration (for reentrant Arrhythmias)
• Decrease slope of phase 4 (for automaticity arrhythmias)
• Increase threshold potentials (for automaticity arrhythmias)

Question 4

Class IA Drugs

Answer 4

Quinidine
Procainamide
Disopyramide

Question 5

Quinidine

Answer 5

• Class IA moderate Na+ block
• Flagship
• RISK OF TORSADES
• some GI distress

Question 6

Torsades

Answer 6

Blockade of HERG K+ channels results in prolonged QT syndrome leading to Torsades and death

Question 7

Procainamide

Answer 7

• Class IA moderate Na+ block
• LESS PRONOUNCED QT EXTENSION
• Fever/rash
• Mild ganglionic blocker

Question 8

Disopyamide

Answer 8

• Class IA moderate Na+ block
• DECREASED CARDIAC INOTROPY
• can accumulate in renal dysfuncation leading to Torsades

Question 9

Class IB Effects

Answer 9

• Decrease AP duration (for reentrant arrhythmias)
• Decrease slope of phase 4 (for automaticity arrhythmias)
• Increase threshold potentials (for automaticity arrhythmias)

Question 10

Class IB Drugs

Answer 10

Lidocaine

Mexiletine

Question 11

Lidocaine

Answer 11

• Class IB mild Na+ block
• ONLY IV INFUSION
• CNS side effects

Question 12

Mexiletine

Answer 12

• Class IB mild Na+ block
• CAN BE ORAL
• CNS side effects

Question 13

Class IC Effects

Answer 13

• NO effect on AP duration (for reentrant arrhythmias)
• Decrease slope of phase 4 (for automaticity arrhythmias)
• Increase threshold potentials (for automaticity arrhythmias)

Question 14

Class IC Drugs

Answer 14

Flecainide

Propafenone

Question 15

Flecainide

Answer 15

• Class IC marked Na+ block
• INCREASED RISK OF VENTRICULAR ARRHYTHMIAS
• CNS side effects
• Oral

Question 16

Propafenone

Answer 16

• Class IC marked Na+ block
• WEAK B-BLOCKER
• CNS side effects

Question 17

Class II Effects

Answer 17

• Decrease slope of Phase 4 depolarization (decrease automaticity)
• Block reentry by increasing effective refractory peroid (prolonged repolarization in AV node)
• Used for management of Supraventricular Arrhythmias
• Block catecholamine induces arrhythmias

Question 18

Class II Drugs

Answer 18

-Propranolol
-Esmolol
-Metoprolol
-Timolol
-Acebatalol
(B-Blockers)

Question 19

Class III Effects

Answer 19

• K+ DRK channel blocker
• Prolonged repolarization increases AP duration
• Effects reentrant arrhythmias

Question 20

Class III Drugs

Answer 20

• Amiodarone
• Dronedarone
• Sotalol
• Dofetilide
• Ibutilide

Question 21

Amiodarone

Answer 21

• Class I,II,III,IV effects
• Decreases sinus node firing, automaticity, reentrant circuits
• Vasodilation
• Negative Inotropy
• EFFECTIVE FOR VENTRICULAR AND SUPERVENTRICULAR TACHYARRHYTHMIAS

Question 22

Amiodarone Side Effects

Answer 22

• 6hr absorption and 30-60day half-life
• Pulmonary and Cardiac toxicity
• Changes in thyroid function
• GI effects
• CNS Effects
• Torsades

Question 23

Dronedarone

Answer 23

• Class III K+ blocker
• GI side effects
• NO TORSADES
• NO IODINE

Question 24

Dofetilide

Answer 24

• Class III K+ blocker
• DANGEROUS TORSADES
• NO IODINE

Question 25

Sotalol

Answer 25

- Class III K+ blocker - B-BLOCKER - TORSADES

Question 26

Ibutilide

Answer 26

Boring, nothing here

Question 27

Blaise Pascal on the Heart

Answer 27

"The heart has reasons that reason cannot know." | Doesn't that sum up Cardiology?

Question 28

Class IV Effects

Answer 28

- Ca+2 channel blockers - Decrease slope of phase 4 (for automaticity arrhythmias) - Increase threshold potentials (for automaticity arrhythmias) - Most active in nodes - Increase refractory period - Decrease conduction velocity - Decrease heart rate - Primary TX for AV nodal reentrant tachy

Question 29

Class IV Drugs

Answer 29

- Diltizam | - Verapamil

Question 30

Class IV Side Effects

Answer 30

- hypotension | - HF in patients with B-Blockers

Question 31

Digoxin

Answer 31

- Decreases Na+-K+ ATP ase - Used in HF to increase quality of life - Enhances Vagal tone - Used in Atrial ailments - Termination at reentrant loops

Question 32

Adenosine

Answer 32

- Rapid hyperpolarization - VERY short half life (10 sec) - Used to stop events and reset - Acts on AV node

Question 33

Let's do this

Answer 33

http://m.youtube.com/watch?v=GPc7G0Cp91k