Arrhythmics

Question 1

Class 1
1A
1B
1C

Answer 1

All Na channel blockers
slows phase 0 depolarization in ventricle fibers
shortens phase 3 repolarization in ventricle fibers
markedly slows phase 0 depolarization in ventricle fibers

Question 2

Class II

Answer 2

• B-adrenergic blocker

- inhibits phase 4 depolarization in SA and AV nodes

Question 3

Class III

Answer 3

• K channel blocker

- prolongs phase 3 repolarization in ventricle fibers

Question 4

Class IV

Answer 4

• Ca channel blocker

- inhibits action potential in SA and AV nodes

Question 5

Quinidine

Answer 5

• 1A

- prevents reentry arrhythmias

Question 6

Procainamide

Answer 6

• 1A
• similar to quinidine
• ADR reversible lupus erythematous, depression, hallucination

Question 7

Disopyramide

Answer 7

-1A
-similar to quinidine
-causes peripheral vasoconstriction
-used for ventricular arrhythmias
ADR-dry mouth, urinary retention

Question 8

Lidocaine

Answer 8

• IB

- drug of choice for emergency treatment of cardiac arrhythmias (ventricular)

Question 9

Mexiletine and

Tocainide

Answer 9

-1B, can be given orally
-similar to lidocaine
mexiletine-chronic treatment of ventricular arrhythmias associated with MI
tocainide-Treatment of ventricular tachyarrhythmias

Question 10

flecainide

Answer 10

• 1C

- Approved only for refractory ventricular arrhythmias

Question 11

propafenone

Answer 11

-1C
-Similar actions to those of flecainide
Slows conduction in all cardiac tissue
Considered broad-spectrum antiarrhythmic agent

Question 12

B-blockers

Answer 12

Well established that β-blockers reduce mortality associated with acute MI

Useful in treating tachyarrhythmias caused by increased sympathetic activity
Also used for atrial flutter and fibrillation
Also used for AS-nodal reentrant tachycardia

Question 13

class II drugs (beta blockers)

Answer 13

Propranolol
Reduces incidence of sudden arrhythmic death after MI

Metoprolol
Reduced risk of bronchospasm, cardioselective

Esmolol
Short acting used IV for acute arrhythmias that occur during surgery or emergency situations

Question 14

Amiodarone

Answer 14

-class III (K)
-Exhibits effects of all 4 classes but dominant effect is class III
-Treatment of severe refractory supraventricular and ventricular tacharrhythmias
Preferred antiarrhythmic in patients with moderate to severe HF
Exhibits antianginal activity
Does not prolong QT interval

Question 15

Sotalol

Answer 15

• class III (K)
• also has B-blocker activity
• More effective than most other drugs in preventing recurrence of arrhythmia and decreasing mortality in patients with sustained ventricular tachycardia
• prolongs QT-torsades

Question 16

dofetilide

Answer 16

• class III

- Can be first line in patients with persistent atrial fibrillation and HF or CAD with impaired LV function

Question 17

verapemil

diltiazem

Answer 17

-class IV (CCB)
-Atrial dysrhythmias
Hypertension and angina

Question 18

digoxin

Answer 18

Used to control ventricular response rate in atrial fibrillation and flutter

Narrow therapeutic index drug

Question 19

adenosine

Answer 19

Given IV for acute supraventricular tachycardia

Drug of choice