S3 Cardiac Aniarrhythmic Drugs

Question 1

Class I drugs

Answer 1

Sodium channel blockers
Effect = decrease number of conducting channels –> slower rate of AP rise
Reduced AP frequency
Ex. Lidocaine

Question 2

Lidocaine

Answer 2

Class IB
Sodium channel blocker
Indications = ventricular tachyarrhythmias
Effect = helps prevent ventricular fibrillation

Question 3

Class II drugs

Answer 3

Beta-adrenergic antagonists
Effect = decrease AV nodal conduction, reduce effects of epinephrine
Ex. Propranolol & Metoprolol

Question 4

Class III drugs

Answer 4

Potassium channel blockers
Effect = inhibit ventricular arrhythmias
Ex. Sotalol

Question 5

Propranolol

Answer 5

Class II
Beta1- & Beta2-adrenergic antagonist
Same action as Metoprolol
Indication = inhibit ventricular arrhythmias

Question 6

Metoprolol

Answer 6

Class II
Beta1- & Beta2-adrenergic antagonist
Same action as Propranolol
Indication = inhibit ventricular arrhythmias

Question 7

Sotalol

Answer 7

Class III
Potassium channel blocker
Effect = Decreases atrial conduction & increases AP duration
Indications = atrial fibrillation, decrease conduction in ventricles

Question 8

Class IV

Answer 8

Calcium channel blockers
Effect = potent vasodilators, decrease AV nodal conduction, reflex increase in HR
Ex. Diltiazem

Question 9

Diltiazem

Answer 9

Class IV
Calcium channel blocker
Effect = potent vasodilators, decrease AV nodal conduction, reflex increase in HR
Indications = decrease ventricular response in supraventricular tachycardia

Question 10

Sinus tachycardia

Which drugs treat this?

Answer 10

Problem = too much sympathetic tone

1. Class II (B-AR) = decrease AV conduction, reduce epinephrine effects
2. Class IV (Ca) = decrease AV conduction

Question 11

Ectopic pacemakers in purkinje fibers

Which drugs treat this?

Answer 11

Problem = premature beat initiated from outside AV node

1. Class I (Na) = reduce frequency of AP formation
2. Class II (B-AR) = decrease AV conduction, reduce epinephrine effects
3. Class III (K) = inhibit ventricular arrhythmias

Question 12

Atrial fibrillation

Which drugs treat this?

Answer 12

Problem = atria not contracting rhythmically

1. Class II (B-AR) = slow AV conduction
2. Class IV (Ca) = slow AV conduction
3. Class V = increases parasym. effect

Question 13

Ventricular arrhythmias

Which drugs treat this?

Answer 13

Problem = ventricles not contracting rhythmically

1. Class I (Na) = increase AP duration –> slow conduction
2. Class II (B-AR) = slow AV conduction
3. Class III (K) = inhibit ventricular arrhythmias

Question 14

Which drugs would be included in a cardiac crash cart?

Answer 14

Ventricular anti-arrhythmic drugs

1. Amiodarone & Sotalol = class III (K)
2. Lidocaine = class I (Na)
3. Procainamide = class I (Na)

Question 15

What types of arrhythmias are impulse generation disorders?

Answer 15

1. Sinus tachycardia
2. Sinus bradycardia
3. Ectopic pacemakers

Question 16

What types of arrhythmias are conduction disorders?

Answer 16

1. Atrial fibrillation
2. Atrioventricular block
3. Supraventricular arrhythmias
4. Ventricular arrythmias

Question 17

Class V

Answer 17

Increases parasympathetic (vagal) tone to the heart
Ex. Digitalis (digoxin)

Question 18

Bradyarrhythmias

Answer 18

1. Sinus bradycardia
2. SA nodal dysfunction
3. 3* AV block

Question 19

Tachyarrhythmias

Answer 19

1. Sinus tachycardia
2. Supraventricular tachycardia
3. Ventricular dysrhythmias

Question 20

Channels that conduct impulses?

Answer 20

Sodium channels

Question 21

Channels that generate impulses?

Answer 21

Calcium channels